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Full text of "A system of anatomy for the use of students of medicine (Volume 1)"

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DUE TWO WEEKS FROM LAST DATE 

SEP 



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SYSTEM OF ANATOMY 

FOR THE USE OF 

STUDENTS OF MEDICINE. 

BY CASPAR WISTAR, M.D. 

LATE PROFESSOR OF ANATOMY IN THE UNIVERSITY OF PENNSYLVANIA. 

WITH NOTES AND ADDITIONS, 
BY WILLIAM E. HORNER, M.D. 

PROFESSOR OF ANATOMY IN THE UNIVERSITY OF PENNSYLVANIA. 



SEVENTH EDITION. 

ENTIRELY REMODELED AND ILLUSTRATED BY NUMEROUS ENGRAVINGS. 

BY J. PANCOAST, M.D. 

LECTURER ON ANATOMY AND SURGERY, ONE OF THE SURGEONS OF THE 

PHILADELPHIA HOSPITAL, FELLOW OF THE PHILADELPHIA 

COLLEGE OF PHYSICIANS, ETC. 



IN TWO VOLUMES. 
VOL. I. 

PHILADELPHIA: 
THOMAS, COWPERTHWAIT & CO. 

1839. 



[ANNE) 






SHntcvrtJ, according to the Act of Congress, in the year 1838, by Thomas, 
Cowperthwait & Co., in the Clerk's Office of the District Court of the 
Eastern District of Pennsylvania. 



9 



>■ 



PREFACE TO THE SEVENTH EDITION. 



The publication of the first edition of his " System of Anatomy for 
the use of Medical Students," was completed by Dr. Caspar Wistar 
in 1814. Simple in its construction, concise, but yet clear, and at 
the same time representing faithfully and fully, the science of Ana- 
tomy as it then existed, the book was exactly in keeping with the 
well known character of its distinguished author. The general ap- 
proval with which it was received in this country, was manifested 
by the rapidity of its sale. 

The second edition was called for in 1817, which was further im- 
proved by the author, by the addition of such new anatomical facts 
as had come to his knowledge, and such further physiological obser- 
vations as served to give life and interest, to the otherwise dry 
details of his science. In 1818, before his work had reached the 
third edition, the author himself died, regretted by all who loved 
virtue, honoured science, or knew how to estimate a kindness of 
soul, and uniform urbanity of manner, which is yet vivid in the re- 
collection of his friends. 

The superintendance of the third edition was assumed by Pro- 
fessor Horner, a personal friend of Dr. Wistar, who has enriched it, 
by the addition of much valuable matter, which the science in its 
onward progress had at that time developed. The value of these 
additions, may be inferred, from the increasing favour which the 
medical public has continued to extend towards the work, four edi- 
tions having been completely exhausted since that period. 

Though fifteen years only have elapsed, since its former revision, 
the zealous and persevering inquiries of modern anatomists, which 
have scarcely their parallel in any other department, have in that 
time added much to the science. The present publishers have there- 
fore been desirous, that the work should be so extended and remo- 
delled, as to be brought up as near as may be, to the existing state 
of the science, without impairing its value as a manual by too much 
increasing its bulk. The reader will discover how far this attempt 
has been successful, by comparing this with former editions. 

Within the period alluded to, the department of general, more than 
that of special anatomy, has yielded the richest harvest to the anato- 
mist, and has been advantageously cultivated with^particular refer- 
ence to physiology and therapeutics. From general, then, more than 
from special anatomy, have the present additions been derived ; the 



V 



31 



IV PREFACE. 

editor believing that in mere special description, that which is most 
concise and yet so comprehensive as not to omit any thing of real im- 
portance, is the best. He has not, therefore, added a great deal to the 
individual description of the bones, ligaments, muscles, blood-vessels, 
and nerves. But in the department of General Anatomy, and espe- 
cially in Splanchnology, the viscera being so important in a medical 
point of view, the student will find the additions to have been both 
numerous, and extensive. 

The department of Neurology, which has been the fashionable 
anatomical study, for years past, and upon which hangs so much 
that is important in physiology and medicine, has appeared to him 
more deficient than any other portion of the original work, as the 
brain and spinal marrow have been described by Dr. Wistar, only 
from above downwards; a method which was, however, the most 
approved and general in his day. — The editor has therefore added 
two entire chapters on that subject, one on the General Anatomy of 
the Nervous System, and one on the special description of the Spinal 
Marrow and Brain, from below upwards, in the order of its deve- 
lopement, and the direction of its functions, retaining, nevertheless, 
here as in other parts, all the original text. It has also been thought 
advisable, to transpose several portions of the work, when by so 
doing, parts belonging to the same general tissue could be placed in 
more natural connexion, and made to correspond with the mode 
in which they are usually described. 

Thus, the account of the brain, the eye and the ear, has been trans- 
ferred from the first volume to the second, and placed in continuity 
with that of the other parts of the general nervous system. To 
facilitate the student in the acquisition of this difficult science, all 
the plates of the former edition, which were sufficiently accurate to 
be useful, have been retained, and several other copperplate engrav- 
ings of the blood-vessels added, with upwards of a hundred wood- 
cuts, some of which are original, but the greater part collected with 
considerable care and labour from the newest and most approved 
sources. 

The amount of the new matter added to this edition is nearly 
equal to a fourth part of the whole. The student will, however, be 
enabled to distinguish readily the original text of Dr. Wistar, from 
the additions which have been made either by Dr. Horner, which are 
all included in brackets [ ], or from those of the present editor, 
which are separated from the other parts of the work by their com- 
mencing and terminating with a dash — . Various synonymes in- 
troduced throughout the work, and some more trifling emendations 
of the text, it has not been thought necessary to designate. 

J. PANCOAST. 
Philadelphia, Dec. 1, 1838. 



DR. HORNER'S PREFACE. 



The value of the present work having been sufficiently tested 
by its very diffused use in the profession, and by a third edition 
being now called for, the editor has been induced to superintend the 
latter, with a hope that its utility and the public conviction in its 
favour have been in no wise diminished. The closeness of the con- 
nexion between himself and its lamented author, furnished, also, 
another and a very powerful reason, why he should endeavour by 
such means as he commanded, to contribute to perpetuate the 
memory of a man whose literary and professional career had been 
so conducive to the reputation of his country, and whose philan- 
thropy and suavity of manners had established him so firmly in the 
affections and confidence of all who knew him. 

Several amendments have been introduced by the way of cor- 
rections, alterations and additions. The latter, for the most part, 
appear between brackets, and in the form of notes, but there are 
many which could not be marked in such a manner without giving 
the text a garbled appearance, they therefore appear as portions of 
the original work. 

The whole mass of matter introduced as amendments is greater, 
indeed, than a superficial perusal of the work would intimate ; and 
the only way for the reader to arrive at it, will be by a careful com- 
parison of the last with the present edition. The editor, however, 



Vi PREFACE. 

has been careful not to allow the spirit of change or improvement to 
affect the work in any points except such as seemed to him abso- 
lutely to require it, and where he was fully warranted by the best 
authorities in Descriptive Anatomy. It would have been sufficiently 
easy for him to have extended the work considerably beyond its 
present dimensions ; but from its having been originally designed as 
a text-book of the course of Lectures on Anatomy in the University 
of Pennsylvania, and for the benefit of practitioners, who are always 
most assisted by condensed views on this subject, he was appre- 
hensive of perverting or of frustrating its objects by such extension. 
In consequence of which he has principally confined himself to add- 
ing where additions were called for by recent discoveries in Anatomy, 
and by the omission of older ones. 

Philadelphia, Oct. 10th, 1823. 



CONTENTS OF VOL. I. 



PART I. 

OSTEOLOGY. 
CHAPTER I. 

GENERAL ANATOMY OP THE OSSEOUS SYSTEM. 

Classification and structure of Bones, - - - 13 
Of the Periosteum, ------ 32 

Medullary Membrane or Internal Periosteum, - 33 

Cartilages and their Structure, - - 35 

Accidental developement of Cartilages, - 38 

Of the Formation of Bone, 39 

Formation of Callus, .... 45 

Terms used in the Description of Bones and Joints, - 48 

CHAPTER II. 

OF THE SKELETON AND ITS DIFFERENT PARTS. 

Of the Head, ...... 51 

Cranium, ------ 52 

Sutures, ------ 54 

Os Frontis and other bones of Cranium, - - 6ti 

Face, ....-- 76 

Ossa Maxillaria Superiora and other bones of the Face, 77 

Teeth, - 88 

Composition of the Teeth, ... 89 

Developement of the Teeth, - - - - 97 

Permanent Teeth, - - - - 100 

Aberrations of Dentition, - - - - 104 

Os Hyoides, - - - - - 105 

Orbit of the Eye, - - - - - 106 

Cavities of the Nose, - - - - 108 

Cavity of the Cranium, - - - - 110 

Basis of the Cranium, - - - - m 

Side of the Cranium, - - - - - 114 

Form of the Cranium, - - - - U5 

Head of the Foetus, - - - - - 118 



vjii CONTENTS. 

Of the Trunk, JJJJJ 

Spine, " \™ 

True Vertebrae, - - - • " j~* 

False Vertebrae, - - - - " J J* 
Vertebral Canal, - 

Thorax, " *° 

Ribs, 36 

Sternum, - - - - : ' A \ 

Pelvis, J 44 

Os Ilium and other bones of the Pelvis, - - l 4t > 

Acetabulum, - - - - - ' 4J 

Cavity of the Pelvis, ----- 150 

Dimensions of the Pelvis, - - - !53 

Trunk of Foetus, - - - - - 154 

Upper Extremities, - - - - 154 

Shoulder, - - - - - -155 

Os Humeri, or Arm-bone, - - - 161 

Forearm, - - - - - - 164 

Hand, ------ 168 

Carpus, - - - - - - 169 

Metacarpus, - - - - - l? 3 

Fingers, ------ 176 

Inferior Extremities, - - - - 178 

Os Femoris, or Thigh-bone, - - - - 179 

Leg, 181 

Foot, - - - - - - - 187 

Extremities of the Foetus, - - - 196 

Explanation of the Plates of Osteology, - - - 199 



PART II. 

SYNDESMOLOGY. 
CHAPTER III. 

GENERAL ANATOMY OF THE LIGAMENTOUS, FIBROUS, OR DESMOID TISSUE. 

Of the Ligaments, ----- 207 

CHAPTER IV. 

OF THE ARTICULATIONS. 

Of the Articulations, - - - - - 214 

Bursae Mucosae, - - - - - 216 



CONTENTS. ix 

CHAPTER V. 

OF PARTICULAR ARTICULATIONS. 

Of the Particular Articulations, - - - ^ - 219 

Articulations of the Vertebrae, - - - 220 

Lower Jaw, ... 223 

Shoulder, 224 

Elbow, .... 227 

Hand, - - - 228 

Ribs, - - - - 231 

Hip, 232 

Knee, .... 233 

Leg and Foot, - - 237 

CHAPTER VI. 

OF SOME PARTICULAR LIGAMENTS, AND OF THE SITUATION OF THE 
INDIVIDUAL BURSiE MUCOSVE. 

Particular Ligaments, .... - 240 

Explanation of the Plates of the Joints, - - - 251 



PART III. 

MYOLOGY. 
CHAPTER VII. 

GENERAL ANATOMY OF MUSCLES. 

General Anatomy of the Muscles, - - - - 255 

CHAPTER VIII. 

OF THE INDIVIDUAL MUSCLES. 

Muscles of the Teguments of the Cranium, - - 273 

Ear, 27 * 

Eyelids, 27 *j 

Eyeball, «J 

Nose, ill 

Mouth and Lips, - - - ' ZJ> 

Lower Jaw, " " " " 22 

Anterior part of the Neck, - - - '-* 8& 



CONTENTS. 



286 

289 
291 
292 



296 

298 



Muscles of the Lower Jaw and Os Hyoides, 
Styloid Process, etc. - 
Fauces, - 

Pharynx, - - - V^L 

Glottis or of the Larynx, - - ^ 

Anterior part of the Neck, - 
Anterior part of the Thorax, 
Ribs (Intercostals and Triang. Sterni), 
Anterior part of the Abdomen, - 
Male Organs of Generation, - - jjjj° 

Anus, - - - „.- 

Female Organs of Generation, - - 6 ™ 

Cavity of the Abdomen, 

Within the Pelvis, - - - " o)~ 

Posterior part of the Trunk, - - 317 

Neck, - - - 321 

Superior extremities (of the Scapula), - 
Os Humeri, ----- ^28 
Front part of the Forearm, 

Back part of the Forearm, - - - 333 

Palm of the Hand, - - - ;^ 

Back of the Hand, - 6 ™ 

Inferior extremities, - - - 340 

Os Femoris, - 

Front of the Leg, ^48 

Back of the Leg, - - - " ? 

Sole of the Foot, - - - 35 

Back of the Foot, - - - - 353 

CHAPTER IX. 

OBSERVATIONS ON THE MOTIONS OF THE SKELETON. 

Of the Motions of the Skeleton, 359 

Explanation of the Plates of the Muscles, - - - 365 



PART IV. 

OF THE GENERAL INTEGUMENTS, OR OF THE CELLULAR MEMBRANE 

AND SKIN. 

CHAPTER X. 

OF THE CELLULAR MEMBRANE. 

Of the Cellular Tissue, ----- 3fi<) 

Adipose Tissue, 



CONTENTS. XI 

CHAPTER XI. 

OF THE SKIN. 

Of the Cutis Vera, ... - - 375 
Sebaceous Follicles, ----- 377 

Rete Mucosum, ----- 379 

Skin, according to Gaultier, - 384 

Breschet, - - - 386 

Cuticle, - - - - - - 394 

Nails, ------ 401 

Hairs, - - - - - - 403 



PART V. 

OF THE NOSE, MOUTH, AND THROAT. 
CHAPTER XII. 

OF THE NOSE. 

Of the Nose, ------ 408 

Eustachian Tube, - - - - - 417 

CHAPTER XIII. 

OF THE MOUTH. 

Of the Mouth, 420 

Tongue, - - - ' - - 424 

Salivary Glands, ----- 430 

Parotid Gland, - - - - - 431 

Submaxillary Gland, - - - 43y 

Sublingual Gland, - - - - - 434 

CHAPTER XIV. 

OF THE THROAT. 

Of the Throat, --""""' }JJ 
Isthmus of the Fauces, - - - "Jo? 

Tonsils, --■■"' Jog 

Larynx, - " 

Cricoid Cartilage, " ' " "' IS 

Thyroid Cartilage, - 4dy 



XU CONTENTS. 

Of the Arytenoid Cartilages, .... 440 

Epiglottis Cartilage, - - - - - 441 

Ventricle of the Larynx, - 442 

Glottis, - - - - - - 443 

Thyroid Gland, .... - 445 

Pharynx, - - - - - - 44d 



PART VI. 

OF THE THORAX. 

Mammary Gland, ..... 449 

CHAPTER XV. 

GENERAL CAVITY OP THE THORAX. 

Of the Form of the Cavity of the Thorax, - - - 452 

Pleura, ...... 453 

CHAPTER XVI. 

OF THE HEART, PERICARDIUM, AND THE GREAT VESSELS CONNECTED WITH 

THE HEART. 

Of the Pericardium, ...... 457 

Heart, ...... 459 

Great Vessels of the Heart, ..... 469 

CHAPTER XVII. 

OP THE TRACHEA AND LUNGS. 

Of the Trachea, ----.. 473 

Bronchia, ----__ 473 

Lungs, ------ 475 

Thorax of the Foetus, - -■ . . 480 

Heart, - - - - . . 48 j 

Lungs, ------ 483 



SYSTEM OF ANATOMY. 



PART I. 

OSTEOLOGY. 

CHAPTER I. 

GENERAL ANATOMY OF THE OSSEOUS SYSTEM. 

Classification and structure of bones — Chemical composition — Recent researches 
on the intimate structure of bone — Periosteum — Medullary membrane— Carti- 
lages — Formation of bone — Terms used in describing bones. 

— The osseus tissue in man and nearly all large animals 
not inhabiting a dense medium, constitutes that scaffolding or 
framework, upon which is supported all the soft parts of the 
body. Hence the bones when seen in connexion in a perfect 
skeleton, present so perfect an outline of the animal to which they 
belonged, as to be sufficient as has been shown by Baron Cuvier, 
to indicate clearly the shape, size, and mode of life of the ani- 
mal as well as the nature of the food upon which it lived.* 
— The bones may be considered as designed for the fulfilment of 
two principal objects — the formation of cavities for the protec- 

* A skeleton, or a structure analogous to it in its uses, that of forming a founda- 
tion upon which the body can be built, and to which the muscles may be attached 
to move it from place to place, is found in the mammiferae, birds, and many fishes, 
in the interior of the body ; in the Crustacea and testacea, some fish, reptiles, &.c. 
it is wholly or in part at the exterior. In a great majority of cases it is bony in 
its structure; it is, however, cartilaginous in many fishes, and fibrous in nearly 
all coleopterous insects of which it forms the external covering. — p. 

VOL. I. 2 



14 CLASSIFICATION OF THE BONES. 

tion of delicate and important organs, as in the head, thorax, and 
pelvis — and of columns and levers for support and motion, as in 
the spinal column and the upper and lower extremities. They 
perform, however, but a passive or mechanical part in the move- 
ments of the body, forming supporting organs round which the 
muscles, nerves and vessels are wreathed, and at the same time 
serve as levers, by which the limbs are lifted. They arc necessa- 
rily very numerous in the human body, and exist as separate and 
distinct pieces, which touch one another at their extremities, 
where they are generally expanded in size, and their parts so 
nicely adjusted to each other, as to form the basis of the struc- 
ture of the joints. At these places of junction, the bones are 
fastened together, by strong fibrous, inelastic, inextensible bands, 
called ligaments. 

— The number of the bones in the human body, varies accord- 
ingly as we examine them, in infancy, middle life, or in old age. 
Nearly all the individual bones of the adult, are developed in 
separate pieces in the infant, the number of which is very great, 
and their consolidation into single bones, is not general and 
complete till about the period of puberty : many of these sepa- 
rate bones of the adult, especially of the head and trunk, are 
found fused together in extreme old age. 

— Anatomists have generally agreed to consider as distinct bones, 
those of the adult, and to these they have given individual names. 
The skeleton is divided into trunk, head, and extremities: 
— Thus there are for the trunk, fifty-three bones ; the twenty- 
four true vertebrae, the sacrum, the coccyx, twelve ribs on each 
side, one sternum in three pieces* and two ossa innominata. 
— For the head, fifty-nine bones; the occipital, sphenoid, ethmoid, 
frontal, the two parietal, two temporal with the four small bones 
of the ear, the vomer, the two superior maxillary, two palatine, 
two malar, two nasal, two lachrymal or unguiform, two inferior 
turbinated, the inferior maxillary, the teeth, and the hyoid bone. 
— For the two upper extremities, seventy-four bones; there are 
on each side, the scapula, clavicle, humerus, radius, ulna, eight 
wrist or carpal bones, five metacarpal, fourteen phalanges, and 
five sesamoid bones. 



CLASSIFICATION OF THE BONES. jc 

— For the two lower extremities, sixty-six bones; on each side one 
femur, a tibia, a fibula, patella, seven ankle or tarsal bones, five 
metatarsal, fourteen phalanges of the toes, and two and some- 
times three sesamoid. Thus according to the enumeration of 
Marjolin, there are two hundred and fifty-two bones in the hu- 
man body. The number of sesamoid bones, however, is very 
variable ; and some anatomists, of high reputation, do not include 
the teeth in the enumeration of the bones of the body. 
— The bones are all either symmetrical or unsymmetrical. The 
symmetrical bones are in pairs, and correspond in size and shape 
very nearly with each other, and are placed upon the side, like 
those of the extremities and ribs. The unsymmetrical, which 
consist of some of the bones of the head, the sternum, vertebrae, 
sacrum, os coccygis and os hyoides, are situated in the middle 
line of the body; the lateral halves of these bones correspond 
very closely with each other. 

— From their general form and geometrical dimensions, the bones 
have been divided into classes; the long bones, ossa longa, the 
broad bones, ossa lata, and the thick bones, ossa crassa. The 
long bones, occupy the centre of the limbs, are the levers used 
in locomotion, and form a series of broken columns, articulated 
together, which increase in number, and diminish in size, as they 
recede from the trunk. They are divided into a middle part 
body or diaphysis; and into extremities or epiphyses. The body 
is cylindrical in some, prismatic and triangular in others, and 
generally a little curved or twisted. The extremities are ex- 
panded and thick. The bodies which are the smallest part, hap- 
pily correspond with the bellies or largest part of the muscles — 
the extremities with their narrow tendinous terminations. 
— The broad bones assist in forming a part of the walls of the 
trunk and head ; they are flattened, more or less concave on 
their interior, varied in their form, and thicker usually at their 
margins, than at their centres. 

— The thick bones are assembled in masses, and form parts at 
once solid and movable as in the spinal column, the wrist, and 
the ankle. 
— The human bones in a recent adult subject, are of a dull white 



16 STRUCTURE OF THE BONES. 

colour : they possess considerable elasticity, but little flexibility, 
have the greatest specific gravity of any portion of the human 
body, and are liable to be broken by violent efforts. Their 
texture is varied not only in different parts of the skeleton, but in 
different parts of the same bones. Thus in the long bones, the 
middle portion or diaphysis is compact, or nearly solid, with a 
cavity in the centre ; the extremities are cellular or spongy, with 
but a thin coating of the compact matter, and the central cavity, 
is occupied by a long network formed of their plates and fibres, 
called the reticulated tissue of the bones. 

— In flat bones the external surfaces are composed of firm plates 
of compact bone; but the internal substance is cellular. In some 
of these bones, the cellular tissue exists in such little quantity, 
that the external compact layers almost touch, and the bones 
become then diaphanous or translucent. 

— The thick bones are formed almost entirely of the spongy or 
cellular substance, which is surrounded by an extremely thin 
shell of the compact bony matter, and are somewhat darker in 
colour than the long or the flat. 

— The osseous tissue thus presents three modifications of form ; 
the compact, the reticular, and the cellular or spongy. The 
compact, which is the densest and strongest, is placed upon the 
outer surface of all the bones of the body ; it forms a covering 
of greater or less thickness to all the flat and thick bones, and 
adds to their strength, without much increasing their weight. 
The long bones, which are narrowed down in the shaft, so as to 
accommodate the muscles, without destroying the symmetry of 
the limbs, and require to be made of the strongest material, have 
their shafts or bodies formed almost entirely of the compact 
portion. The cellular or spongy is found, in a greater or less de- 
gree, in every bone of the body ; in the extremities of the long 
bones it is continuous, though indirectly, with the reticulated 
tissue of the central or medullary canal. The reticulated tissue 
has been considered only a modification of the spon°y, being 
formed of larger cells of a more delicate texture. — 

[The cellular structure of bones is attended with several im- 
portant advantages. In the cylindrical bones it gives great 
additional strength, by increasing their rliamptor tI .;thA.n *aa;„~ 



STRUCTURE OF THE BONEri. ij 

to their weight ; for by swelling out their articular extremities, 
it produces much greater security of the joints, by obviating the 
tendency to dislocation, and rendering their movements more 
steady. A simple experiment will satisfy any one that the in- 
crease of volume in the extremities of the long bones, is not 
attended with an increase of osseous matter; for in the dried 
bone, the section of an inch from the centre will weigh as much 
as the same length from the extremities, notwithstanding the 
greater size of the latter. Dr. Physick has pointed out another 
very important advantage of the cellular structure of bones, 
besides those of its making them nearly as strong as if they 
were solid, and at the same time diminishing what otherwise 
would have been a weight too oppressive for the muscular 
powers. He thinks that thereby the concussion of the brain, 
and of the other viscera is frequently prevented; and in nearly 
all cases diminished, in falls and in blows. He illustrates the 
position by showing, first, the concussion which takes place 
through a series of ivory balls suspended by threads ; if one be 
drawn to some distance from the others, and allowed to impel 
them by falling. The momentum in this case impels the ball at 
the farther end of the row, almost to the distance from which 
the first one fell. But if a ball of the same size, composed of 
the cellular structure of bone, be substituted for one of the ivory 
balls, and the experiment be repeated, the momentum of the 
first ball is lost almost entirely in the cellular structure of the 
substitute ; particularly if the latter be well soaked previously in 
water, so as to give it a condition in point of moisture allied to 
the living state. Adopting this experiment as demonstrative of 
the fact, Dr. Physick asserts, that in falls from an eminence 
upon the feet, the percussion, by the time it has passed through 
the cellular structure of the foot, leg, thigh, vertebral column 
and the condyles of the occiput, is very much diminished in 
force, and carries much less impulse upon the brain. Again, in 
blows on the head, the brain, though much protected from exter- 
nal injury by the arched form of the cranium, has an additional 
security from the interposition of the diploe, which weakens the 
force of the blow. 

2* 



18 STRUCTURE OF THE BONES. 

In all the bones there are canals, independent of the cellular 
structure, which penetrate to a greater or less extent between 
the lamina, and go in various directions, some longitudinal, 
others oblique and transverse. These canals transmit the blood- 
vessels, and were first pointed out with exactitude by Clopton 
Havers, an English anatomist.* But he assigned a wrong appli- 
cation to them, as he believed that the marrow ran through 
them, in order to make the bones supple, and to unite their la- 
mina more strongly. S. B. Albinus corrected the mistake, by de- 
monstrating that they were filled with blood-vessels. These canals 
in a vertebra are particularly large, and open on the posterior 
face of its body, by one or two large foramina. In the cranium 
they are remarkably well seen ; but their discovery is of more 
modern date. M. Portal says, that in the bones each kind of 
vessel has a particular canal for itself alone; those of the arteries 
are therefore to be readily distinguished from such as belong to 
the veins and to the nerves; and this takes place both in the 
large and in the small canals. Occasionally the vessels dip into 
a common canal, but if any one will take the trouble to follow 
them, he will find them ultimately separating from each other.] 

— The canals for the transmission of blood-vessels, which exist 
in abundance in the compact bony tissue, cannot be well seen 
in the healthy state, except by the aid of the microscope. With 
the aid of this instrument they may be seen in great numbers, 
running in a longitudinal direction, opening in its internal or me- 
dullary cavity, so as to maintain a free communication between 
the vessels on the exterior, and those in the cavity of the bone. 
— When cut in surgical operations, blood issues from the com- 
pact substance, which is susceptible of inflammation, and its conse- 
quences, like other vascular parts. In inflammation, the compact 
portion, is sometimes seen swelled and expanded, so as to de- 
velope in its substance, a cellular arrangement, somewhat like 
that of the common spongy tissue. Maceration of a bone in 
water, after its earthy part has been removed, exhibits the 
same arrangement. In fact, the principal difference between 

* These canals are about one-twentieth of a line in diameter according to 
Beclard, but much less agreeably to Deutsch and Miescher. p. 



STRUCTURE OF THE BONES. 



19 



these varieties of bony tissue, consists in their difference of den- 
sity, with some variation in the disposition of their fibres; the 
cells being condensed in the compact portion so as to admit of a 
decrease in the diameter of the bones, without a corresponding 
diminution of their strength. Hence the amount of substance 
being tfi2 same, in the extremities and shafts of the long bones, 
sections of equal length must of course be of equal weight. — 

A fibrous structure is very obvious in the bones of young sub- 
jects, and in some bones which have been slightly calcined. 

A lamellated structure may also be demonstrated in many bones. 

In the firmness of their texture and their general aspect, bones 
resemble inorganic matter, but there are the strongest proofs 
of their organization. 

For example, if a bone be macerated in certain acid liquors, 
the earthy matter will bedissolved,and a membranous or cartilagi- 
nous substance will remain, resembling the bone in form and size.* 

Jf the bones of a young subject, after being injected, be treated 
in the same way, this membranous substance will appear to be 
very vascular — when the injection has been successful, it will 
appear uniformly reddened by the greatest number of vessels 
which are filled with the matter of injection. These vessels dis- 
charge blood when the periosteum is removed from the surface 
of bones, in the living subject, and they also form granulations 
upon bony surfaces that have been thus denuded. 

— On the other hand if a recent bone be exposed for a con- 
siderable time to the action of a moderate fire, or boiled for a 
long period in a Papin's digester, the other element of the bone 
may be obtained — its earthy structure — in a separate state, re- 
presenting the original perfectly, in size and shape. It is then 
perfectly white, and is so light and brittle as to crumble on the 
slightest touch. 

— Exposure of bones for a long time to the action of the climate, 
will cause it to shell off in layers and fall into powder, from the 
same cause, the destruction of its animal matter. 

* One part of muriatic acid to thirty of water is a good mixture for this purpose, 
by taking care to keep up the strength of the mixture by additions of the acid 
from time to time. — h. 



20 STRUCTURE OF THE BONES. 

— A bone macerated in acid, or well incinerated, may be torn or 
split in particular directions, more readily than others, and mani- 
fests an evident fibrous arrangement. 

— In regard to the disposition and arrangement of these fibres, 
anatomists differ, though it has been with them a subject of much 
research. The length of each fibre is limited, running but a 
small part of the length of the long bones, but is much greater 
than its breadth and thickness. The greater part are longitu- 
dinal, that is, run in the direction of the axis of the bone; some 
are transverse and some oblique. From the shortness and varied 
direction of the fibres, and the cellular appearance of the bone 
when macerated, Scarpa has denied entirely, the existence of a 
fibrous arrangement in the bones, and considers them composed 
throughout, exclusively of cellular substance, more or less com- 
pacted. 

— Malpighi and Havers, believed the bones made up wholly of 
concentric lamellae, formed of fibres and filaments, encrusted 
with osseous matter, laying over each other like the leaves of a 
book. Gagliardi believed, also, that these lamellae were united 
together by little pins of the same material: some of which 
were straight, some oblique, and some he fancied had round 
heads. De Lasone, says that these lamellse are made up of ossi- 
fied fibres, united by oblique ones, and Reichel, that the lamella? 
and fibres, form a porous, tubulated tissue, continuous with the 
spongy substance. According to J. F. Meckel, the proper sub- 
stance of the bones, is of a fibro-laminated nature, the fibres 
in some parts being so closely aggregated, as to form compact 
bone, and separated and expanded in others, so as to form the 
cells of the spongy portion. The longitudinal fibres are much 
the most numerous, one leaning against, and terminating near the 
commencement of another, so as to give an imperfect appear- 
ance of continuity throughout the bone. These fibres at the ex- 
tremities of the bones, are lost in the spongy or cellular tissue 
which they assist to form. The transverse and oblique,* serve to 
connect the longitudinal fibres together, and are united with them 
uninterruptedly upon their sides ; in the spongy portions, thev 

* These represent the uniting pins of Gagliardi. 



STRUCTURE OF THE BONES. 21 

appear also, to assist in the formation of the cells. They are 
both most abundant in early infancy, and as the bones increase 
in length, are directed more in the axis of the bone, till the 
oblique seem nearly lost in the longitudinal, and the transverse 
become more oblique. 

— The fibres of the different layers of the compact bone, are 
united to one another more intimately upon the sides, than to the 
layers below, hence a bone exposed to the action of the weather 
or the fire, shells off in scales, or in certain morbid states during 
life, as necrosis, exfoliates in layers.f 

— From these investigations the osseous tissue, may be justly 
considered as formed of an animal or membranous basis, analo- 
gous to the common cellular tissue and cellular fibre, in other 
parts of the body, and differing from it only in its being imbued 
or incrusted with inorganic earthy matter, which gives it firm- 
ness and strength, but at the same time renders it liable to frac- 
ture. The cells of the bones, like those of the cellular tissue of 
the soft parts of the body, are all imperfect, having openings by 
which they communicate with one another, and may be all 
readily injected, with any fluid sufficiently thin to run; and if 
fluid mercury be used it will make its way through the vascular 
foramina to the external surface. — 

The existence of absorbent vessels, and even of nerves, in 
bones, is equally certain with that of the blood-vessels, but they 
are not easily demonstrated. 

[The French anatomists have occasionally traced branches 
of the fifth pair of nerves going along with the nutritious arteries 
into some of the bones; but as yet no other nerves have been 
seen by them. M. Portal speaks in familiar terms of the exis- 
tence of both nerves and lymphatics in the bones, as if he had 
often noticed them ; he, however, has omitted to inform us of 
the source, from which the former come.] In the sound state 

t Mr. Howship of England, from some recent microscopical observations on the 
bones, has been led to support the opinion of Scarpa, that the ultimate tissue of all 
the bones, is of a reticular nature. This is evidently true, in regard to the ulti- 
mate analysis of bones, when the course of the fibres has been destroyed by pro- 
longed maceration, or by suppurative inflammation.— p. 



22 CHEMICAL COMPOSITION OF THE BONES. 

bones have no sensibility, but pain is often felt in them when 
diseased. 

—We cannot doubt the existence of the absorbent vessels in 
bones, since Cruikshank and Sommering, affirm it from their 
own observation, and from their own injections. Breschet, has 
observed it many times, and Bonamy, in making a mercurial in- 
jection of the inferior extremities, " was able to follow them for 
some time in the interior of the osseous tissue." 
—They possess (according to Bichat,) a certain degree of exten- 
sibility and retractility, which is developed so slowly as to be 
almost insensible in its progress. These properties are demon- 
strated in the expansion of the bones of the face, from tumours of 
the antrum, and in the retraction of the sockets of the teeth, 
after the loss or removal of the latter. — 

Modern chemistry has ascertained that the earthy matter of 
bones is principally a phosphate of lime; carbonate of lime, in 
a smaller quantity, is also found in them. These earthy sub- 
stances compose near one-half of the weight of bones, and a 
large proportion of the remainder appears to be gelatinous and 
cartilaginous matter. 

— The chemical composition of bones will be found to vary, in 
the different ages of life, and in some measure according to the 
individual bones selected for investigation; the inner compact 
plate or vitreous table of the cranial bones, and the petrous 
portion of tha temporal, possessing a greater relative amount of 
earthy matter than any other bones in the body. From these 
causes, arises considerable discrepancy in the analysis given by 
different chemists. In early life the relative proportion of earthy 
matter is at its minimum, the animal at its maximum. In ad- 
vanced age, the reverse holds good, when the bones are notori- 
ously brittle and liable to fracture. Diseased conditions of the 
system are known to still further modify these proportions: in 
childhood the earthy matter may be so much> diminished that 
the bones become plastic and yielding, as in rickets; and at later 
periods of life, it preponderates occasionally so much over the 
animal as to render them liable to break at the slightest shock, 
as in cases of frogihtas ossium; and in some of the venereal 



CHEMICAL COMFOSITIO\ OF THE BONES. 23 

affections, the bones are rendered nearly as solid and heavy as 
a piece of ebony. 

— The earthy matter of the bones of the higher animals consists 
chiefly of phosphates of lime, with carbonate of lime, and a 
small quantity of phosphate of magnesia, and fluate of lime. 
— The phosphate of lime of the bones is a subsalt, according to 
Miiller, in which the base and acid are combined in peculiar 
proportions, and which is always obtained when biphosphate of 
lime is precipitated by an excess of ammonia. The phosphate 
of lime of the urine is a super-salt, and is in solution, and in the 
disease called mollities ossium, seems to be excreted in a state 
of solution in the urine in larger quantity than natural. The 
following is the result of Berzelius' analysis of the bones in man 
and the ox: 

Cartilage* completely soluble in water 
Vessels .... 

Neutral phosphate of lime 
Carbonate of lime 
Fluate of lime 
Phosphate of magnesia 
Soda with a small proportion of chloride 
of sodium - 

100.00 100.00 

— Schreger states that in the bones of a child, the earthy matter 
constitutes one-half, that in the bones of an adult it amounts to 
four-fifths, and in those of an old person to seven-eighths of the 
whole mass. 

— Fourcroy and Vauquelin, found no fluate of lime in their 
analysis, but met with some iron, manganese, silex, alumine, and 
phosphate of ammonia. The luminous appearance of bones at 
night, when the animal matter is undergoing decomposition, is 
believed to be owing to the phosphorus liberated from combina- 
tion, and in such instances, Bichat has found an oily or unctuous 
exudation at the luminous points. 

* i. e. Gelatine. 



Man. 


Ox. 


32.17 ) 
1.13 \ 


33.30 


51.04 


55.45 


11.30 


3.85 


2.00 


2.90 


1.16 


2.05 


' 1.20 


2.45 



24 RECENT RESEARCHES ON THE INTIMATE STRUCTURE OF BONE. 

— Gerdy* has very recently investigated the structure of the 
bones, and his observations which coincide with the microscopical 
researches of the German anatomists (shortly to be noticed,) ap- 
pear to have set at rest many of the conflicting opinions upon 
the subject. He considers that there are four distinct tissues in 
bone, which have been confounded together up to this time; the 
compact, the canaliculated, reticular, and areolar or cellular. 
— The compact tissue has in certain bones a fibrous appearance; 
its fibres appear longitudinal in long bones, radiated or irregu- 
larly divergent in many of the flat. The whole of this fibrous 
appearance is illusory, as Scarpa asserted, and is owing to the 
grooves or canals in the compact portion of the bones which 
lodge vessels, (canals of Havers,) run longitudinally in the 
compact portion, and have orifices leading into them from the 
outer surface; between the canals is found projecting the proper 
structure of the bone, which is necessarily thin, and from the 
great number of these vessels, presents the appearance of fibres. 
The vascular openings leading into the grooves, are some per- 
pendicular, and some oblique in regard to the surface of the 
bones. They all conduct vessels into the compact tissue. The 
compact tissue, as will be better seen under the head of formation 
of bone, is primitively a compound of osseous tubes developed 
around the vessels. These osseous tubes which are longitudinal 
in the long bones and radiated in the flat, are so numerous, fine, 
so closely compressed together and so adherent, that their ar- 
rangement has escaped the observation of anatomists. The ex- 
istence of these vessels in the forming bone is well understood, and 
they have been injected with mercury by Tiedemann in the parie- 
tal bone.f In the adult healthy bone, they are more difficult of 
detection, in consequence of the dense nature of the compact 
substance, in which the vascular channels of the bones and the 
vascular orifices on the surface are reduced nearly to a micro- 
scopical size. But when the bony tissue is diseased or inflamed, 
as in fractures or after amputations, their existence is no longer 
doubtful. Blood issues from them when cut, and the vascular 
orifices, on the surface as well as the canals in the compact tissue 

* Bulletin de Clinique, 1835-6. t See Breschut, Plates of the Venous System.— p. 



GERDY ON THE INTIMATE STRUCTURE OF BONE. 



Mb 




are visible to the naked eye, and in some in- 
stances are said to have been as large as a 
pigeon's quill. Fig. 1, is a view of these canals, 
as seen in a bone twenty-five days after am- 
putation. When the orifices and canals are 
thus expanded, the compact tissue appears 
rarefied, rough on its surface, more light and 
fragile and corresponds in appearance with 
the canaliculated tissue of Gerdy. 

The absence of fibrous appearance on the thick and mixed 
bones is dependent upon the direction of the canals, none of 
which run parallel to the surface, but are all directed towards 
the articular surfaces of the bone. In the foetus at birth the 
compact portion of these bones appears sieve-like, from the 
number of vascular orifices on the surface, which lead perpen- 
dicularly to the canals that run towards the centre of the bones. 
Hence, according to Gerdy, the compact layer of these bones, 
is made up of minute bony rings, surrounding the numerous vas- 
cular orifices which touch each other at their circumference 
like the rings round the orifices of a tin colander.f 

The canaliculated tissue, is developed in all the bones of the 
body, but is least evident in the flat. It is an assemblage of 
small canals traversed by vessels, and has heretofore been de- 
scribed as a part of the cellular or spongy. In the long bones 
it is found on the inner surface of the compact tissue, and sepa- 
rated from the reticulated tissue of the medullary canal, by a 
parchment-like lamin, pierced with holes for the passage of 
anastomosing vessels. These canaliculi form elongated cavities, 
which are slightly tortuous, nearly parallel with one another, 
not exactly rounded and have their parietes pierced with holes to 

* Fig. I. Section of the extremity of the os femoris, twenty-five days after ampu- 
tation. It appears cribiform from the number of irregular orifices, belonging to 
the canals of Havers (canaliculi,) in the compact portion of the bone. The 
vessels which occupy these canals, are greatly enlarged by inflammation. Cases 
of this sort have been confounded by writers, with inflammation of the veins of 
the bones. — p. 

+ This we shall find is the opinion of the microscopists in regard to the struc- 
ture of all compact bony layers. — p. 

VOL I. 3 



26 



GERDY ON THE INTIMATE STRUCTURE OF BONE. 



Fig. 2* 



admit of anastomosis, between 
the vessels which line them ; 
they run in the long bones in 
the direction of their length, 
and in the thick bones, from 
one articular surface to the 
other. They arise in part from 
the divisions of the nutritious 
foramina, which transmit the 
medullary vessels of the long 
bones, but chiefly from the vas- 
cular canals of the compact 
tissue (Haversian,) as seen in a 
vertical section of the femur 
and tibia, fig. 2 and fig. 3, 
where the increase of the ca- 
naliculated structure is in in- 
verse proportion to the thick- 
ness of the compact. These 
canals unite together, and di- 
vide, again and again, so that 
they become increasingly nu- 
merous as they approach the 
spongy extremities, when they 
separate from each other and 6 
spread out so as to form a large part of these extremities. 
— The cellular or areolar tissue of Gerdy, is formed in the thick 

* Fig. 2. Vertical section of the inferior third of the tibia. 1.1. Compact tissue 
of the body of the bone, becoming gradually thinner towards the inferior extremity. 
2. 2. Reticulated tissue in the lower part of the medullary cavity and occupying 
the axis of the cylinder of bone. 3. 3. Canaliculated tissue, the vascular canals of 
which detach themselves successively from the compact walls of the bone, and 
run nearly parallel with each other towards the extremity of the bone. 4. 4. Cel- 
lular tissue of the epiphysis, composed of interrupted canaliculi, and of tubular 
cells, which terminate nearly perpendicularly upon the articular surface. 6. 6. The 
articular or sub-cartilaginous compact tissue extremely thin. Very generally it 
is deficient in places on the articular surface of bones, so as to leave the cells of 
the spongy tissue and their vascular canals naked when the cartilage is removed. 
7. Internal malleolus. — p. 




GERDY ON THE INTIMATE STRUCTURE OF BONE. 
Fig. 3.* 



27 




bones and the extremities of the long bones by the interruptions 
of the canaliculated tissue, by other canals arising from the 

* Fig. 3. Vertical section of the os femoris. 1.1. Tubular cells perpendicular 
to the articular surface of the bone; sometimes these cells are chiefly round- 

2. Cartilaginous lamin separating the epiphysis from the shaft of the bone. 

3. Vertical canal opening by one or more foramina, in the forsa at the top of 
the trochanter, and anastomosing with the canals of the canaliculated tissue. It 
lodges one of the vessels of the cellular tissue, which penetrate by the extremity 
of the body of the long bone. 4. 4. Vascular canaliculi, which run obliquely up- 
wards and inwards towards the lamen of the epiphysis, where the cartilage begins 
to be removed, and the consolidation of the epiphysis and shaft has commenced. 
5. 5. Canaliculi of the upper part of the body of the bone, which are directed 
towards the axis of the bone, and which anastomose with the vascular canal indi- 
cated at 3. 6. Conical termination of the reticulated tissue of the medullary 
canal. — p. 



28 GERDY ON THE INTIMATE STRUCTURE OF BONE. 

surface of the bone which cross them in an angular direction, so 
as to form quadrilateral cells, see Fig. 3, 1, the partitions of which 
are pierced, so that there is a free communication between the 
vessels lining the different cells. 

— The reticulated tissue which was confounded by Bichat with 
the canaliculated, should be now as it was before his time dis 
tinguished from it. So far from being formed of a canaliculated 
tissue for the purpose of containing vessels, it consists only of a 
network of bony filaments for the purpose of supporting a deli- 
cate cellular membrane called the medullary which is thrown 
into the form of cells, to retain the fat or marrow, and which is 
very vascular. It is found chiefly in the cavities of the long 
bones, and terminates short of the extremities in a point, see Fig. 
3, 6, while the canaliculated tissue continues to expand. This tis- 
sue is beautifully developed in the long bones of the horse, but 
scarcely exists at all in those of the bullock. 
— Vessels of the bones. All anatomists admit three kinds of ves- 
sels in the bones ; those of the compact tissue, those of the cel- 
lular tissue, those of the medullary canal. 

— Those of the compact tissue are very fine and very numerous; 
they penetrate it in great numbers, after having divided to capil- 
lary minuteness in the periosteum. Having entered the compact 
tissue, they spread in its channels (canals of Havers, canaliculi 
of Gerdy,) which are imperceptible without a microscope in a 
healthy bone, but become very manifest in disease. 
— Those of the medullary canal enter usually by a single lar^e 
foramen, give off some branches to the canaliculi in their course, 
and having reached the medullary or central cavity, divide into 
two branches, which run in opposite directions towards the extre- 
mities of the bone. These branches divide and subdivide very mi- 
nutely in the medullary membrane, and anastomose very freelv 
with the vessels of the canaliculated tissue upon the side, and in 
the adult, (after the cartilage which separates the epiphysis from 
the body of the bone has been removed,) with the cellular tissue 
of the extremities. 

— Those of the cellular tissue, that is to say the vessels of the 
extremities of the long bones and the large vessels of the other 



DEUTSCH AND MIESCHER ON THE INTIMATE STRUCTURE OF BONE. 29 

bones, penetrate from the surface by foramina much larger than 
those of the compact bone, and occasionally under the form of 
distinct canals. They anastomose intimately with the other two 
orders of vessels, and are particularly abundant near the articu- 
lar surface of the bones, where they form the tubular cells, and as 
some suppose directly or indirectly assist in the formation of the 
articular cartilages, which appear to be a simple product of ex- 
cretion like the nails or hair. All the vessels are surrounded in 
the canals by a cellular tissue, more or less delicate, loose and 
filled up with a fatty or oily matter, which is least abundant 
in the compact tissue where the canals are very small. These 
facts in regard to the structure of bone are supported both by 
observation and reasoning. 

— The microscope shows us thousands of vessels in the healthy 
state entering into the substance of the bones. Inflammation 
attended with vascular congestion developes and renders them 
so obvious as to be appreciated by the unassisted eye, the slight- 
est irritation with a probe will cause them to bleed freely, and 
heat applied to a section of a recent bone, will develope the fatty 
or oily matter even in the compact portion. 
— From the complexity of their organization, and the frequency 
and importance of their diseases, bones demand from the student, 
more earnest study, at least in regard to their general anatomy 
than is usually given. — 

Deutsch,* under the direction of Purkinje, and Miescherf of 
Berlin, whose investigations were made prior to those of Gerdy, 
and with the aid of the microscope, have arrived at nearly simi- 
lar conclusions, in regard to the structure of bone. 

In very thin transverse sections of long bones, which had been 
macerated in dilute acid, they discovered the circular orifices of 
the longitudinal canals in the compact portions of the bone; and 
in thin longitudinal sections they were seen divided in the direc- 
tion of their length. (See Figs. 4 and 5.) 

These circular canals, according to these observers, commu- 

• De penitiori ossium structura observationes. Vratislavire, 1834.— p. 
t De ossium geneai, struclura et vita. Berolini, 1836. — p. 

3* 



30 DEUTSCH AND MIESCHER ON THE INTIMATE STRUCTURE OF BONE. 

nicate here and there with each other, and constitute the longi- 
tudinal and transverse canals of Havers, and which are described 
by Lewenhoeck, as his third and fourth kinds of pores. 

Fig. 4.* 

c 




'd, cL 

—These canals are filled with yellowish medullary or adipose 

matter, in which according to Miescher, are seen many minute 

capillary vessels, when successfully injected after the method of 

Krause. 

Fig. 5 * 




— In the transverse section, each of the orifices of the canals. 

* Fig. 4. Is a longitudinal section of a long bone, magnified one hundred times. 
a. One of the longitudinal canals not fully exposed, b. b. Longitudinal canals 

c. c. These canals partially cut across, so as to exhibit the concentric lamellee 
which surround each one. d. d. Transverse canals joining the others. The 
straight lines near the margins of the cut, are the lamella-, divided in the direction 
of their length, which surround the canals. 

* Fig. 5. Is a transverse section of one of the flat bones of the cranium, simi- 
larly magnified, a. a. Compact substance or table of bone, expanding into di- 
ploe, b. b. c. Vasculo-medullary canals of the compact portion, cut across. 

d. Transverse communicating canals, between these and the larger canals or cellu- 
lar cavities of the diploe. e. Diploic cells communicating with others at/. Diploic 
cells like the canals of the compact portion, are surrounded with concentric stria? 
or lamellae, and are in fact only amplified vasculo-medullary canals. The spots 
upon the surface, are the bony corpuscles. 



DEUTSCH AND MIESCHER ON THE INTIMATE STRUCTURE OF BONE. 31 

Fig. 5, are seen surrounded by ten or fifteen concentric lines, 
which on examining the longitudinal section, Fig. 4, are found 
to be as many lamellae running the whole length of the canal, 
and each about the 7 |oth part of an inch in diameter, ac- 
cording to the microscopical measurement of Deutsch. The 
spaces in the transverse section of the bone, not occupied by the 
longitudinal canals and their concentric lamella?, are filled by 
other lamellae, which form larger concentric rings around the 
great medullary cavity. The diameter of the canals of Havers, 
according to Miescher, varies from i^th to - 8 £ 7 th of an Eng- 
lish inch. 

— In the flat bones the canals with their lamellae, run parallel 
with the surface of the bone. In the long bones, the longitudinal 
canals are directed obliquely into the central cavity. 
— In the lamellae concentric to the canals, there is an appear- 
ance of dots or short lines, which do not occupy the whole 
thickness of each lamella, and which Deutsch, was probably in 
error, in supposing to be extremely minute tubes. Some of 
these dots or lines, see Fig. 5, appear to traverse more than 
one lamella though the majority, as Miescher describes them, 
are very short, and appear like the separations between the gran- 
ules of the cartilage of the bones, from which the calcareous 
portions had been removed. The result of the observations of 
Miescher, is: 

— 1st. That the spongy structure of bones, is nothing but an 
amplification of the canaliculi, as is shown by Gerdy. 
— 2d. That the medullary canal, as shown by its formation 
and name, is provided for the purpose of union or anastomosis, 
between these enlarged canaliculi, and, 

— 3d. That therefore, the canaliculi, girdled with concentric 
lamellae and containing a medulla, composed of a great body of 
vessels, is the primary element or form of the osseous tissue, 
which is subsequently more fully developed. 
— Scarpa therefore says rightly, that the solid parts of bone, are 
formed of the cellular structure in a more compacted state. The 
reticulated tissue, which forms a sort of link between the cellular 
substance and the medullary cavity, and the osseous filaments 



32 OF THE PERIOSTEUM. 

which project every where from the parietes of the cavity, into 
the medulla, are the remains of the walls of the cells, the inte- 
grity of which is impaired in consequence of the enlargement of 
the orifices by which they communicate together. — 

Of the Periosteum. 

Bones are invested with a firm membrane denominated -peri- 
osteum, which is of a fibrous texture, and in some places may be 
separated into different lamina. The external surface of perios- 
teum is connected with the contiguous parts by cellular mem- 
brane; the internal surface is connected with the bone by a great 
number of fibres and blood-vessels. The orifices of these 
vessels appear, when the periosteum is separated from bones in 
the living subject. 

This membrane covers the whole bony surface, except those 
parts which are invested by cartilages, and the capsular liga- 
ments of joints ; those which are occupied by the insertion of 
tendons and ligaments, and the bodies of the teeth. It appears 
most intimately connected with the surfaces of spongy bones, 
and the extremities of the long bones. In a sound state it has 
very little sensibility; but in some cases of disease it appears to 
be very sensible; of course it must be supplied with nerves, 
although several expert anatomists have declared they could not 
trace them. 

It is probable that the principal use of the periosteum is to 
transmit vessels to the bones for their nourishment; but death or 
exfoliation of the surface, does not always take place when the 
periosteum is removed from a portion of bone.* 
— This membrane presents a polished, pearly white appearance, 
when examined in the recent bone. It has received different 
names according to the parts which it covers, though its struc- 
ture is nearly uniform throughout. Thus, where it covers the 
exterior surface of the bones of the cranium it is called pericra- 

* Dr. Physick thinks that the periosteum frequently prevents the bones from 
participating in contiguous disease, as the pleura turns off an abscess in the pa- 
rietes of the thorax from its cavity, or the peritoneum from the cavity of the ab- 
domen. — H. 



OF THE MEDULLARY MEMBRANE OR INTERNAL PERIOSTEUM. 30 

nium ; when it covers the cartilages, perichondrium ; and when 
it covers the bones with the exception of those of the head, pe- 
riosteum. 

— In infancy the periosteum is soft, thick, and spongy? and may 
be readily separated from the bones. In adult life it is more 
firm and compact, and is often so intimately united, as to be de- 
tached with difficulty from the bones. In old age it is extremely 
dense, and becomes not unfrequently ossified at its internal sur- 
face. Its vascularity, which is at first rather obscure, also gra- 
dually increases as life advances, but in old age it again dimi- 
nishes.* 

Of the Internal Periosteum or Medullary Membrane. 

— This membrane is particularly well marked in the cavities of 
the long bones, where it forms a thin, delicate, pellucid, vascular 
tissue, lining the sides of the cavities of the reticulated tissue, in 
which it forms vesicles, that contain the marrow. 
— The lining membrane of the cells in the spongy portion of the 
bones is still more delicate in its structure, and more difficult of 
demonstration, and has been supposed by many anatomists to 
be formed only from the coats of the blood-vessels which anas- 
tomose thousands of times with each other in the interior of these 
bones. Its office, however, is precisely similar to that of the 
membrane in the cavity of the long bones, to lodge the fatty or 
medullary matter which is furnished by exhalation. It is very 
inflammable, burning with a beautiful blue tinge, and an oily, 
disagreeable odour, fluid during life, but presents itself after death, 
under the form of brilliant granules of solid fatty matter. When 
death has taken place from some wasting disease as dropsy or 
consumption, the fat is removed by absorption, and its place is sup- 
plied by a watery fluid which renders the bones less greasy and 
more valuable as cabinet preparations. This medullary sub- 
stance as has been before observed is also found with the ves- 
sels in the canals of the compact portions of bone. — 

At the extremities of the long bones, the foramina for the 

* Anat. Pbys. and Diseases of Bones and Joints. By S. D. Gross, M. D. 



34 F THE MEDULLARY MEMBRANE OR INTERNAL PERIOSTEUM. 

transmission of the blood-vessels and fibres are much larger than 
they are in the middle; but there is an oblique canal near the 
middle of these bones, which transmits vessels to this membrane 
in the interior of the bones called nutritious or medullary. 

The surface of the internal cavities and cells of bones it will 
then be seen, is lined by a membrane, more delicate and more vas- 
cular than the periosteum, which contains the medullary matter 
that is always found in their cavities. [This is the internal peri- 
osteum or the medullary membrane of the bones. M. Portal 
denies that it exists as a distinct membranous sac, but asserts, 
that it is derived from the envelope of the vessels which is sent 
in along with them from the periosteum.] 

It has been said that in some circumstances this membrane 
has had great sensibility, but the reverse is the case in common. 

The medullary matter in the large cavities of bones has a 
strong resemblance to adeps. That which is in the cells, at the 
ends of the long bones, appears more fluid. In young animals 
it is slightly tinged with a red colour. 

—The chemical properties of the adipose or medullary sub- 
stance of the bones consist according to Berzelius of the follow- 
ing ingredients: 

Pure adeps or marrow .... 96 

Membrane and blood-vessels - - 1 

Albumen ..... 

Gelatine ..... 
Extractive and peculiar matter - 
Water ..... 



100 

— The character of this substance differs somewhat at the dif- 
ferent stages of life; it is of a thin aqueous consistence and of a 
reddish colour in the infant; of the consistence and presenting 
after death somewhat the appearance of butter in the central 
cavities of the bones, and of a red semi-fluid appearance in the 
spongy tissue of the bones of the adult ; in old age it has some- 
thing of a rancid smell, and is of a deep yellow colour. The 
adeps of the bones was supposed at one time to contribute to 



CARTILAGES AND THEIR STRUCTURE. oc 

the flexibility, tenacity, and nourishment of the bones, but it is 
now generally believed to be deposited upon the same principles, 
as fat in other parts of the body when nutritive matter is supera- 
bundantly elaborated by the digestive organs, and is held in re- 
version, as an aliment for the future wants of the economy, 
during temporary inanition from sickness or other causes. 
— The deposit of fat in bones is not universal among animals. 
In birds the central cavity of the long bones, is filled only with 
air which is introduced into them from the lungs, and serves 
greatly to diminish their specific gravity, and facilitate their 
evolutions in the atmosphere. 

— It is found in great quantity in the bones of the head of the 
physeter macrocephalus, or sperm whale, far out of the proportion 
required, if its object only was that of nourishing the bones. 
— Its purpose in this animal, besides being a deposit of aliment 
in reserve, is believed to be that of buoying up its head to ena- 
ble it to respire with greater freedom. — 

Cartilages and their Structure. 

Cartilages are white elastic substances, much softer than 
bones, in consequence of a smaller quantity of earth entering 
into their composition. 

Their structure is not so evidently fibrous as that of bones; 
yet by long maceration, or by tearing them asunder, a fibrous dis- 
position is perceptible. 

In articular cartilages their fibres are parallel to each other, 
and directed towards the cavities of the respective joints. 

Their vessels are extremely small, though they can be readily 
injected in cartilages where bone is beginning to form. The 
vessels of the cartilages of the joints, however, seem entirely to 
exclude the red blood ; no anatomists having yet been able to 
inject them. They have no cancelli, nor internal membranes, 
for lodging marrow; no nerves can be traced into them; nor do 
they possess any sensibility in the sound state. 

Upon their surface, there is a thin membrane termed peri- 
chondrium, which in cartilages supplying the place of bone, as 
in those of the ribs or at the ends of long bones in children, is a 



36 CARTILAGES AND THEIR STRUCTURE. 

continuation of the periosteum, and serves the same general pur- 
poses to cartilage as this does to bone. 

Upon the surface of articular cartilages, the perichondrium is 
a reflection of the inner surface of the capsular ligament, and is 
so very thin, and adheres so closely, as to appear like part of 
the cartilage itself.* 

One set of cartilages supplies the place of bone, and by their 
flexibility admit of a certain degree of motion, $J^le their elasti- 
city recovers their natural position, as in the nose, larynx, carti- 
lages of the ribs, &c. 

Another set, in children, supplies the place of bone, until bone 
can be formed, and affords a nidus for the osseous fibres to shoot 
in, as in the long bones of children. 

A third set, and that the most extensive, by the smoothness 
and lubrication of their surface, allow the bones to move readily, 
without any abrasion, as in the cartilages of the joints. 

A fourth set supplies the office both of cartilage and ligament, 
giving the elasticity of the former and the flexibility of the latter, 
as in the bones of the spine and pelvis. 

— Next to the bones, the cartilages form the hardest tissue in 
the body. On first inspection they do not appear to present any 
sort of internal organization. They appear homogenous in their 
texture and inorganic. When more carefully inspected, how- 
ever, and especially in the articular cartilages, a particular struc- 
ture is apparent. 

— According to De Lasone and Hunter, the articular cartilages 
are composed of fibres implanted perpendicularly to the surface 
of the bones, and parallel with each other, like the villi or threads 
upon a piece of velvet. In this manner the cartilages covering 
the bones forming the joints, which are invested with the syno- 
vial membrane, rub against each other, not upon the sides, but 
upon the ends of the fibres, which brings the elasticity of the lat- 
ter, into play. The perpendicular direction of these fibres may 
be made apparent by maceration, or by sawing down a recent 

* The articular cartilages are the only ones not provided with a fibrous peri- 
chondrium. The synovial membrane which is reflected over them from the inner 
face of the capsular ligament, appears to supply the place of perichondrium.— r. 



CARTILAGES AND THEIR STRUCTURE. 0-7 

bone, and splitting through its cartilage — and they are believed 
byBecIard, to constitute the free numerous and floating flocculi, 
which are seen on the surface of cartilage in its transformations 
from disease. 

— It is very probable that there is some cellular tissue in the 
composition of cartilages : when carefully incinerated, the re- 
mains present a cellulated appearance. Its existence is rendered 
still more probable, by their being developed in the foetus in a 
mould of cellular tissue, and from fleshy granulations, being seen 
occasionally to spring from their surface in various parts of the 
body. 

— When a recent cartilage is cut, a whitish juicy fluid is seen 
to exude from its substance, which must get into it, by imbibi- 
tion from the surrounding parts, or what is more probable, be 
carried into it, by white vessels, too small to admit more than 
the serous portions of theblood. If inflammation take place, which 
is admitted in many cartilages, though not as yet proven to exist 
in those of the joints, it differs from ordinary inflammation as these 
vessels are never so dilated, as to admit the red globules, and 
present a red appearance. No lymphatics have ever been traced 
into them, though Mascagni, was disposed to consider them as 
formed entirely of these vessels; nor have nerves been found in 
them, the very existence of which in these parts, though so ne- 
cessary to the perfection of other organs, would have unfitted 
them for their office. Hence we find them smooth, so as to 
move upon one another without friction, destitute of nerves, so as 
to bear pressure without sensation, and feebly supplied with vessels, 
so as to be little prone to inflammation, if they be not, as Gerdy 
has suggested, a mere secretion like the hair and nails. Hence 
they are enabled to bear exposure to the air for a considerable 
time without change, as stated by Velpeau, and to exist unharmed 
frequently in the midst of gangrene. 

— According to J. Davy, their chemical composition is 55. 
parts in the hundred of water, 44.5, of albumine, and .5 of phos- 
phate of lime. As in the bones, however, the chemical pro- 
portions vary at the different periods of life. They are nearly 
fluid in the fetus, contain a large amount of fluid in youth, have 

VOL. 1. 4 



38 ACCIDENTAL DEVELOPEMENT OF CARTILAGES. 

the proportions given above at puberty, and a much larger 
amount of earthy matter in old age. In fact, with some few ex- 
ceptions in the joints, they all have a natural tendency to ossify 
as life advances. 

— The structure of cartilage is, however, not fully understood : 
that they share in some manner in the genera] circulation of 
the body, is rendered probable by their being coloured yellow in 
jaundice, and that they are not reddened when an animal is fed 
upon madder, like the bones, is said by Beclard, to be owing to 
the small quantity of phosphate of lime, which they contain, and 
with which this substance only has affinity. They participate 
too in the ulcerative process in many parts of the body, as in 
those of the nose, and as I have many times seen, in those of the 
larynx and trachea. 

— All cartilages are divided into two classes, temporary, or os- 
sescent, and permanent, a distinction which though not perfectly 
exact, is nevertheless very convenient for the purposes of study. 
The temporary cartilages, {cartilag temporaries) are those em- 
ployed in the developement of the bones, those of which the 
models of the bones are all formed in the foetus, and which gra- 
dually as the infant advances in growth give place to bony mat- 
ter. The substitution of bony matter for the cartilaginous, is 
completed about the period of puberty. 

— The permanent cartilages (cartilag permanentes) are de- 
veloped at an early period of life, like the former, but have little 
tendency to undergo ossification, and retain their cartilaginous 
character for the whole or the greatest part of life. These com- 
prise, the articular and costal cartilages, those of the larynx, 
eustachian tube, auditory meatus, etc. Some of these have a 
stronger tendency than the rest to ossify, as those of the larynx 
and ribs, which are frequently found after the fortieth year of 
life, converted into bone. 

Accidental developement of Cartilages. 

— In almost every one of the different tissues of the bodv, car- 
tilages have been occasionally met with, but in general onlv 



OP THE FORMATION OF BONE. ,. q 

after the middle period of life, which from their having appa- 
rently no fixed laws of developement, have been called acci- 
dental. 

—1st. They are found in the form of plates of greater or less 
size, adherent by both surfaces to the membranes between which 
they are formed ; in the arteries, where these plates are most fre- 
quently met with, they are attached on their inner surface to the 
serous HningJ^mbrane, and on the outer to the middle coat of 
the vessel. 

— 2d. They are frequently met with in the form of roundish 
or irregular masses in the substance of the different organs, as 
the arteries, lungs and ovaries. 

— 3d. Under the form of smooth flattened concretions, formed 
originally according to Meckel, on the outer side of the synovial 
membrane of the joints, and which develope themselves towards 
the centre of the cavity of the joints, till their attachment to the 
membrane is stretched out, so that it becomes a mere pedicle, 
which not unfrequently breaks off. These form then the loose 
cartilages so often met with in the knee joint. 
— All these accidentally developed cartilages have a tendency 
to be converted into bone, and which are then called accidental 
ossifications. — 

Of the Formation of Bone. 

The generality of bones, and particularly those which are 
long, are originally formed in cartilage ; some, as those of the 
skull, are formed between membranes, and the teeth in distinct 
bags. 

When ossification is about to begin in a particular part of a 
cartilage, most frequently in the centre, the arteries, which were 
formerly transparent, become dilated, and receive the red blood 
from which the osseous matter is secreted. This matter retains, 
for some time, the form of the vessels which give it origin, till 
more arteries being by degrees dilated, and more osseous mat- 
ter deposited, the bone at length attains its complete form. 

During the progress of ossification, the surrounding cartilage 




4Q FORMATION OF BONE. 

by degrees disappears ; not by being changed into bone, but by 
$n absorption of its parts, the new-formed bone occupying its 
place. 

The ossification of broad bones, as those of the head, begins 
by one or more points, from which the osseous fibres issue in 
rays, as seen in Fig. 6. Fig.Q.* 

The ossification of long bones, as in those 
of the extremities, begins by central rings, 
from which the fibres extend towards the ends 
of the bones. 

The ossification of spheri-formed bones, 
begins by one nucleus, as in the wrist ; and 
that of irregularly shaped bones by different 
nuclei, as in the vertebra?. 

Some bones are completely formed at the time of birth, as the 
small bones of the ear. 

The generality of bones are incomplete until the age of pu- 
berty, or between the fifteenth and twentieth year, and in some 
few nstances until a later period. 

In children, many parts of bones, particularly the ends of long 
bones, are distinct from the bodies ; they are called epiphyses, and 
can be readily separated from the bodies of bones, by boiling, or 
by maceration in water. 

The epiphyses begin to appear after the body of the bone is 
ossified, and are themselves ossified at seven or eight years of 
age, though their external surface is still somewhat cartilaginous. 

They are joined to the body of the bone by the cartilages, 
which are thick in children, but gradually become thinner as os- 
sification advances, till at last, in the adult, the external marks 
of division are not to be seen, though frequently some mark of 
distinction may be observed in the cancelli. 



* Parietal boss, of the infant at birth magnified, showing the central point of 
ossification. At first sight the vascular canals, resemble radiated lines, but with 
a little attention, they will be found to be vascular channels, slightly tortuous, and 
originating near the centre of the boss or protuberance from the foramina in the 
newly formed bone. — p. 



FORMATION OF BONE. 



41 



— The developement of bones is the final result of several succes- 
sive changes. In the foetus the bone is at first represented, by a 
soft gelatinous mass, continuous throughout as one piece, and id 
which there is no appearance of joints. The consistence of this 
matter gradually increases, and presents a cartilaginous appear- 
ance, about the second or third months of fetal life. At the same 
period a separation is manifested at the place of the joints. A 
third change takes place in the cartilage, which is that of ossifica- 
tion; this commences in some of the bones, between the second 
and third months of foetal life, at various periods in other bones, 
in many not till long after birth, and is not completed in all the 
bones of the body till near the period of puberty. 
— In the metamorphosis of cartilage to bone, the white and ho- 
mogeneous cartilage which forms the mould of the bone, be- 
comes hollowed out so as to present irregular cavities,* which 
subsequently form canals lined by a vascular membrane and 
filled with a viscous fluid, which extend to the centre of its 
structure. One of these canals forms subsequently the nutritious 
fbramen. The cartilage becomes opaque and yellowish round 
this spot, the vessels convey red blood, numerous red points are 
formed in the structure, and ossification commences at the centre, 
of the bone ; never upon the surface. In the long bones a bony 
ring is first formed in the centre, and the vascular canals ex- 
tend themselves in the direction of the extremities — in the flat 
and thick bones, in radii, attended by a redness in the cartilage, 
nearest the seat of ossification, and a diffused yellowness beyond 
it. From these canals the ossific material is deposited, and the 
central point of ossification grows, till the bone is completed. As 
the bony portion advances in growth, its redness diminishes, and 
the vascular canals which are at first large, decrease in size, so 
as to become in the adult bone microscopical. The ossescent 
or provisional cartilage of the bone, is solid and has in no in- 
stance any cavity in its centre. The ring of bone which, as 

* According to the German anatomists, see page 44, the hollowing of these 
canals, is produced by an aggregation of the cartilaginous corpuscles, into a series 
of linear ranges between which the vessels shoot that convey the earthy material 
of the bone. — r. 

4* 



42 GROWTH OF BONE. 

before observed, is the first step of developement in the long 
bones, has a cavity in its centre which is subsequently destined 
to lodge the medulla. In the flat bones and especially those of 
the cranium, ossification commences between the second and 
third months of fetal life. Those of the cranium are formed 
between the pericranium and dura mater, and their cartilaginous 
mould is so thin and soft, that Howship and Beclard have de- 
nied its existence. The vascularity commences in them at a 
central point, and the ossific rays pass off in a straight direction, 
as seen in Fig. 6, page 40. 

— Many of these bones, as well as of those in other parts of the 
body, are of such irregular shape, as to be incapable of being 
formed of fibres radiating from a single centre; they are, there- 
fore, developed from several centres, the rays of which finally 
meet and inosculate. The developement of the thick bones, and 
the epiphysis of the long bones, takes place in accordance with 
the same laws. 

— Growth of Bones. In all the long bones, the extremities or 
epiphyses, are developed in separate pieces and between them 
and the ossified shaft there is a cartilaginous lamen, which does 
not disappear till the bone has attained its full developement. 
The bones increase in length by the continuous deposit of new 
ossific matter in this lamen of cartilage, which seems retained 
there as a soft bed for that purpose. As soon as the bone has 
attained its full length at puberty, the lamen disappears, and the 
epiphysis and shaft are consolidated, as seen in Fig. 3, where 2 is 
the layer of the cartilage, beginning to disappear at one point. The 
long bones increase in diameter, by the successive addition of new- 
bony matter between the periosteum and bone. It is said to be 
deposited from the periosteum itself: but that opinion is incorrect, 
for no membrane can form a tissue, so much at variance with 
its own structure. It is the blood-vessels which merely ramify 
minutely through the periosteum, that deposit the matter upon 
the surface of the bone, precisely as they do in the centre. This 
mode of growth in diameter by concentric circles, has been 
proved by experiments made with mixing madder at intervals 



OSSEOUS CORPUSCLES. 40 

in the food of animals, by Duhamil,* Hunter, and Professors 
Horner and Mussey. On killing the animals, red rings were 
found surrounding the bones, alternated with white ones cor- 
responding to the periods of administering or suspending the 
madder.f At the same time, that there is this increase of 
matter on the surface, there is a corresponding enlargement in 
the central or medullary cavity, which is said to be effected by 
the action of the absorbents. It appears to me, however, to be 
tar more likely, owing to an interstitial growth by which the 
walls of the cavity are increased in dimensions and the cavity 
itself necessarily enlarged. 

— Corpuscles. Purkinje has recently discovered in cartilage gene- 
rally, and especially in the cartilage of bone, rounded corpus- 
cles, which are much larger in diameter than the transverse 
sections of the canals described in p. 30. The existence of these 
corpuscles, has also been confirmed by the microscopical re- 
searches of Deutsch, Miescher and Sharpey, and according to 
Miescher they correspond with the brown spots described by 
Lewenhoeck as his second order of foramina. In bone deprived 
of its earthy parts by maceration in acid, their appearance is 
that of small brown spots, pellucid in the centre, and surrounded 
with a distinct opaque line, which by a high magnifying power, 
appeared to Miescher to be denticulated. They are situated be- 
tween the lamella?, their long diameter being oblique in regard to 
the direction of the lamellae, and when the work of ossification 
has not commenced, appear to have no fixed arrangement, and 
are wedge-shaped, oval, oblong, or flattened, see Fig. 7, p. 44. Of 
the nature of these corpuscles, little is positively known. Neither 
vegetable or mineral acids have any effect upon them except to 

* Duhamil who was no anatomist, considered the growth of bones, as analogous 
to the vegetation of plants. He placed a silver ring upon the bone of a young 
animal, which he afterwards fed interruptedly on madder. The white and red 
strata alternately covering the ring as he found on killing the animal, he errone- 
ously considered not deposited on the outer surface, but formed by the expansion 
of the bone bulging over it as takes place in plants. — p. 

t Rutherford, of Edinburgh, explained this colouring of the bone, without that 
of the other tissues, by the affinity of the madder for the phosphate of lime, upon 
which it acted as a mordant. — p. 




44 NEW VIEWS OF THE GROWTH OF BONES. 

render them a little more prominent, on the Fig. 7.* 

surface of a section of cartilage. Alcohol, 

CO ton <l&. 

ether, or a cold solution of caustic pot- i&fsf® 
ash has no effect upon them ; but if ex- 
posed to a hot caustic solution, or a long 
time macerated in water they become 
completely liquified. 

— The size of the corpuscles according 
to the measurements of Miescher, varied 
in length from the 0.0048 to the 0.0072 
parts of a line, and in breadth from 
the 0.0017 to the 0.0030. The re- 
searches of this anatomist, of Miiller, and other recent observers, 
have shown that the formation of cartilage always precedes that 
of bone,f and that each ossescent or temporary cartilage, is an 
organic tissue, homogeneous, more or less pellucid, elastic, in its 
first state almost colourless, afterwards assuming a bluish cast, 
and having a great many peculiar minute corpuscles interspersed 
through its substance, as shown by the microscope. 
— In the conversion of cartilage into bone, the change first com- 
mences in the cartilage that surrounds the corpuscles, and sub- 
sequently the cartilaginous corpuscles themselves receive either 
in their centre or in their parietes the calcareous deposit, so that 
the ossification of each temporary cartilage is but an evolution, 
or natural developement which the part is destined to undergo. 
— Weber, Beclard and others, believe that the calcareous matter 

* Fig. 7, is a representation from Miescher of the progress of ossification, caused 
by inflammation in an adult bone, which takes place precisely in the same manner 
that new bone is formed ; a a, the cartilage, the first stage in the formation of bone, 
and the small bodies thickly interspersed through it are the corpuscles of Purkinje; 
h b, the first or primary stage of the bony structure, in which the corpuscles ar- 
range themselves somewhat into lines, and the bony fibres shoot in between them, 
and in the thickness of the corpuscles themselves saline particles are deposited, 
which renders them opaque; c c, the new structure completely ossified. 

t This which was admitted by Albinus, Haller, Scarpa, and others, has been de- 
nied by Howship and Beclard, in regard to the diaphysis of the long bones, and 
the bones of the cranium. In the bones of the rabbit, Miescher found a mould of 
cartilage before a particle of ossific matter had been deposited, and between the 
pericranium and dura mater, a thin stratum of cartilage. 



FORMATION OF CALLUS. 



45 



is deposited by the vessels, in the cartilaginous mould of the 
bone, as a foreign body, and that the cartilaginous particles 
are removed in proportion to make room for it; but this is a 
mere opinion which has not been proven. 

— Miescher, asserts that he was unable even with the microscope 
to ascertain in what manner, the calcareous particles were re- 
ceived into the cartilage, the strongest powers of the microscope 
exhibiting no cells in which they were placed, nor any calcareous 
particles of the size of the dispersed corpuscles ; all that appeared 
positively was that the cartilage seemed by degrees to assume 
the aspect of bone. 

Formation of Callus. 

— The most ancient opinion, in regard to the mode of union be- 
tween broken bones, was, that it was owing to the concretion of 
a viscous fluid, or imaginary osseous juice poured out between 
the fragments. This was the opinion of Haller. Duhamil de- 
monstrated the fallacy of this opinion, by numerous experiments, 
and instituted a theory of his own which is much nearer the 
truth. According to him the production of callus or new bony 
matter, is owing to the swelling, elongation, and subsequent ad- 
hesion between the periosteum and medullary membrane of one 
fragment with the corresponding parts of the other; and that 
from these membranes thus modified, bony matter was deposited 
in the form of a ring on the exterior of the bone and a plug in 
its medullary cavity, which held the fragments together by pass- 
ing across the cavity of fracture, and sometimes by prolongations 
passing between them through the cavity. John Hunter believed 
that the reunion of fractured bones took place from the organi- 
sation of the blood effused around the fracture and between 
the fragments ; a doctrine which now has no supporters. 
— The credit of giving the most faithful account of the formation 
of callus, is due to Dupuytren* and Sanson. According to these, 
the union of fragments of bone, is effected by the formation of 
two successive stages of callus. One which is provisional or 

* Journal Univ. de Med. torn. 20. 



4(} RESTORATION OF FRACTURED BONES. 

temporary, is completed usually in the space of thirty or forty 
days, by the union and ossification of the periosteum, cellular 
tissue, and even in some cases of the muscles, so as to constitute 
an external ring, and of the medullary membrane, so as to con- 
stitute an internal plug. The other, which he calls definitive or 
permanent, is formed by the reunion of the surfaces of the frac- 
ture, with a solidity so much superior to that of the bone in 
other parts, that it will break any where again, rather than at 
that point, and which is never fully completed under eight, ten, or 
twelve months, by which time all the provisional callus has been 
removed, and the medullary canal is completely re-established. 
— Dupuytren divides the successive organic changes, which at- 
tend the formation of callus, into five -periods. 
— The^rs^ period, extends from the time of the fracture to the 
eighth or tenth day, and is characterised by the following pheno- 
mena : when a fracture takes place, the medullary membrane, 
the medulla, the periosteum, cellular tissue, and sometimes the 
muscles themselves, are torn ; blood escapes from the ruptured 
vessels, surrounds the fragments, spreads in the medullary canal 
and infiltrates in the surrounding tissue: the hemorrhage stops; 
a slight inflammation is developed in all these parts, which is 
the first step towards the production of the callus. The cellular 
tissue surrounding the bone, becomes very vascular, is thickened, 
loses its elasticity, and acquires a great degree of consistence ; 
it sends irregular processes into the neighbouring muscles, trans- 
forms them to a greater or less extent into an analogous tissue, 
and unites them in a common structure with the periosteum, 
which is also much thickened and very vascular. A nearlv 
similar change takes place in the cavity of the bone in the me- 
dulla, and. its membrane. The calibre of the medullary canal is 
contracted by the thickening of the membrane, which presents a 
fleshy appearance, in consequence of a sort of gelatinous infiltra- 
tion. The effused blood becomes absorbed, and a ropy, viscous, 
gelatinous fluid, is poured out between the ends of the fragments, 
and is essential to the production of the definitive callus. 
— The second period extends from the tenth or twelfth, to the 
twentieth or twenty-fifth day. During this period, the engorgement 



RESTORATION OF FRACTURED BONES. 47 

of the surrounding parts diminishes and the muscles are liberated: 
but the cellular tissue remains condensed, and concentrated 
round the fracture, presenting grooves or even canals to the 
tendons of the muscles if any pass in the vicinity of the fracture, 
in which they can play, though with little freedom, in conse- 
quence of some existing induration of the cellular tissue. This 
constitutes the provisional callus, the external portion of which 
is thickest at the place of fracture, and insensibly terminates 
upon the fragments of bone. Its internal portion is formed by 
the periosteum, which is closely attached to the bone. Its struc- 
ture is whitish, homogeneous, and of a cartilaginous or fibro-car- 
tilaginous character. The medullary membrane forms a similar 
plug of provisional cartilaginous matter, which fills up the whole 
cavity of the bone, above and below the place of fracture. The 
viscous or gelatinous fluid interposed between the ends of the 
bones, is now rose-coloured or red, and presents sometimes a 
flocculent appearance, and is adherent by its margins to the ex- 
ternal and internal callus. The limb may still be bent at the 
place of fracture, but no crepitation can be produced. 
— The third period extends from the twentieth or twenty-fifth day, 
to the thirtieth, fortieth or sixtieth, according to the age and 
health of the patient. 

— Ossification commences in the centre of the cartilage, and by 
degrees the whole tumour, internal and external, becomes osseous. 
It is very vascular, and Howship* has succeeded in injecting the 
vessels. If at this period the bone be cut longitudinally, the 
provisional callus will be found presenting all the characters of 
spongy bone, while the fragments will be found movable upon 
each other, the substance poured out between them, not having 
apparently undergone much change. 

— The fourth period extends from the fiftieth or sixtieth day, to the 
fifth or sixth month. During this period the callus has been 
changed from the state of spongy, to that of compact bone. 
— The substance intermediate to the fragments, which presented 
itself under the form of a line or septum between them, becomes 

* Microscop. Observ. 



48 TERMS USED IN THE DESCRIPTION OP THE BONES AND JOINTS. 

more consistent, presents a whiter hue, and is ossified towards 
the end of this period ; and the definitive callus is now completed. 
— The fifth period extends from the fifth or sixth, to the eighth, 
tenth or twelfth month, during which time the whole of the pro- 
visional callus is entirely removed, the object of its formation 
having been effected, that of securely holding the bones together, 
like splints, till the fractured surfaces become firmly reunited. 
The periosteum resumes its usual thickness and polish, and the 
muscles and tendons their entire freedom of motion. 
— The internal plug of callus having been removed by absorp- 
tion, the central cavity of the bone, the medullary membrane, 
and the marrow itself, present their usual appearance. — 

Of the Terms used in the Description of Bones and their 
Articulations. 

The study of this subject has been rendered more difficult by 
the unnecessary introduction of many hard words, but some of 
these words are so generally used, that they ought to be under- 
stood by the student of anatomy. 

The word process signifies any protuberance or eminence aris- 
ing from a bone. 

Particular processes receive names from their supposed re- 
semblance to certain objects ; and their names are very often 
composed of two Greek words, thus the term coracoid, which 
is applied to a well-known process, is derived from the Greek 
words xo£«g, a crow, and si5oj, resemblance. 

If a process has a spherical form, it is called a head. If the 
head is flattened on the sides, it is denominated a condyle. 

A rough protuberance is called a tuberosity. A ridge on the 
surface of a bone is called a spine. 

The term apophysis is nearly synonymous with process. It 
signifies a protuberance that has grown out of the bone, and is 
used in opposition to the term epiphysis, which signifies a portion 
of bone growing upon another, but distinct and separable from 
it ; as is the case in infancy with the extremities of the long 
bones. 

The cavities on the surfaces of bones are named in the same 



V ; 



TERMS USED IN THE DESCRIPTION OF THE BONES AND JOINTS. 



49 



way, as will appear by a reference to the glossary at the end of 
this work. 

Words of this kind have been used most profusely in the 
descriptions of articulations, and here also their utility is doubt- 
ful. Therefore, for many terms used on this occasion, the reader 
is referred to the glossary ; but the following are necessary to be 
understood. 

Symphysis does not merely imply the concretion of bones origin- 
ally separate, as its derivation imports ; but it is understood 
also to mean the connexion of bones by intermediate sub- 
stances. Thus, there are three species of symphysis, particu- 
larly noticed, viz. 

Synchondrosis, when bones are connected to each other by car- 
tilage; as the ribs and sternum. 

Synneurosis, when they are connected by ligaments, as in the 
movable articulations. 

Syssarcosis, when they are connected by muscle. The different 
articulations are of two kinds, viz. Synarthrosis and Diar- 
throsis. 

Synarthrosis is the name of that kind of articulation which does 
not admit of motion. There are three species of synar- 
throsis, viz. 

Suture, when the indented edges of the two bones are received 
into each other, as is the case with the bones of the cranium. 

Gomphosis, when one bone is fixed in another like a nail in a 
board, as the teeth in their sockets. 

Shindylesis, when the thin edge of one bone is received into a 
narrow furrow of another, as the nasal plate of the ethmoid 
in the vomer. 

Diarthrosis is the name of that kind of articulation which ad- 
mits of motion. Of these articulations there are three species, 
viz. 

Enarthrosis, when a large head is received in a deep cavity, 
as the head of the thigh bone in the acetabulum. 

Arthrodia, when the head is connected with a superficial cavity. 

VOL. I. 5 




50 TERMS USED IN THE DESCRIPTION OF THE BONES AND JOINTS. 

Ginglimus, when the extremities of bones apply to each other so 
as to form a hinge. 

But most of the important joints have so many peculiarities 
that they cannot be understood without studying them separately. 
It may, therefore, be doubted whether the classification and 
arrangement of joints is any way necessary. 



OF THE HEAD. cj 



CHAPTER II. 

Of the skeleton and its different parts, and the individual bones of which they are 

composed. 

The bones of an animal arranged and connected to each other 
in their natural order, separate from the soft parts, compose a 
skeleton. 

The skeleton is said to be natural when the bones are con- 
nected by their own ligaments, which have been allowed to re- 
main for that purpose. 

It is called artificial when the bones are connected with wire, 
or any foreign substance. 

The artificial skeleton is best calculated for studying the mo- 
tions of the different bones, because the dry and hard ligaments 
of the natural skeleton do not allow the bones to move ; but the 
bones of young animals do not admit of the preparation neces- 
sary for an artificial skeleton, as their epiphyses would separate, 
and they are therefore formed into natural skeletons. 

The study of the skeleton and its mechanical properties, as a 
piece of machinery, is absolutely necessary to a perfect under- 
standing of many motions of the body, and of the action and co- 
operation of muscles; but any observations on this subject will 
be better understood after the individual bones and the muscles 
have been described. 

The skeleton is divided into the head, the trunk, the superior 
and the inferior extremities. 

Of the Head. 

The head comprehends the Skull, or Cranium, and Face. 

The cranium consists of eight distinct bones, which, when 
placed in their natural order, form a large spheroidal cavity for 
containing the brain, with many foramina or apertures that com- 
municate with it. 



52 OF THE CRANIUM. 

These bones are of a flattened form. They are composed of 
two lamina or plates called tables, with a cellular structure be- 
tween them, called meditullium, or diploe. The external table 
is more firm and thick than the internal. The latter is compa- 
ratively very brittle, whence it is called the vitreous table. [Be- 
tween the two tables which compose the flat bones of the cranium 
and running through the diploe are several sinuses, which are oc- 
cupied by veins in the recent subject. They were discovered by 
M. Fleury about twenty years ago, while he was Prosector at 
the School of Medicine in Paris, and engaged in some inquiries 
relative to the structure of the cranium at the instigation of 
M. Chaussier. The account which M. Chaussier gives of these 
veins is as follows: they are situated in the middle of the diploe 
between the two tables of the skull, and like all other veins are 
intended to return the blood to the heart. They are furnished 
with small valves, have extremely thin and delicate parietes, 
and commence by capillary ramifications coming from the dif- 
ferent points of the vascular membrane which lines the cells of 
the diploe. Their roots are at first extremely fine and numer- 
ous, form by their frequent anastomoses a kind of network, and 
produce by their successive junction, ramuscles, branches, and 
large trunks, which, becoming still more voluminous, are direct- 
ed towards the base of the cranium. Some varieties exist in 
regard to the number, size, and disposition of these trunks, but 
generally one or two of them are found in each side of the 
frontal bone, two in the parietal bone, and one in each side of 
the occipital bone. Anastomoses exist between these several 
trunks, by which the veins in the parietal bone are joined to 
those in the frontal and in the occipital. Branches from the 
right side of the head also anastomose with some from the left 
side. Besides the branches already mentioned, one or two 
smaller than the others are directed towards the top of the head 
and terminate in the longitudinal sinus. 

The descending veins of the diploe communicate in their 
passage with the contiguous superficial veins, and empty into 
them the blood which they receive from the several points of the 
diploe. These communications are produced through small fora- 



OF THE CRANIUM. 53 

mina which penetrate from the surface of the bone to the diploe. 
The trunks of such diploic veins as are continued to the base of 
the cranium, open partly into sinuses of the dura mater, and 
partly into the venous plexus at the base of the pterygoid apo- 
physes, and form there the venous communications called the 
emissaries of Santorini. Moreover, there are communications 
sent from the diploic veins through the porosities of the internal 
table of the skull to the veins of the dura mater. This fact is 
rendered very evident by tearing ofTthe skull cap, when the sur- 
face of the dura mater will be studded with dots of blood, and 
the internal face of the bone also, particularly in apoplectic sub- 
jects. It appears indeed that the arteries of the cranium are 
principally distributed on its external surface, and the veins on 
its internal surface and diploe. 

In the infant the diploic veins are small, straight, and have 
but few branches : in the adult they correspond with the descrip- 
tion just given ; and in old age they are still more considerable, 
forming nodes and seeming varicose. In children, when the 
bones are diseased, they partake of the latter character. In order 
to see them fully, the external table of the skull must be removed 
with the chisel and mallet, both from its vaults and base.]* 

The periosteum, which is on their external surface, is called 
pericranium. Internally the dura mater, or membrane which 
covers the brain, supplies the place of periosteum. 

There are eight of these bones, which are thus denominated : 
Os Frontis, Ossa Parietalia, Ossa Temporwn, Os Occipitus, Os 
Sphenoides, and Os Ethmoides. The two last are called common 
bones, to denote that they are connected with the bones of the 
face as well as with those of the cranium. 

The os frontis forms the whole fore part of the vault of the 

* The diploe, or meditullium, corresponds exactly in structure and situation 
with the spongy, or cellular tissue of the other bones of the body, though it has 
unnecessarily received a distinct name. Neither are the diploic sinuses peculiar 
to the bones of the skull. They are found presenting exactly the same appearance 
in the bodies of the vertebrae, and appear in fact to be but a developement of the 
canaliculated tissue of the other bones. See Fig. 5, page 30. — p. 

5* 



54 THE SUTURES. 

cranium : the two ossa parietalia form the upper and middle part 
of it ; the ossa temporum compose the lower part of the sides ; 
the os occipitis makes the whole hinder part and some of the 
base ; the os ethmoides is placed between the orbits of the eyes, 
and the sphenoides extends across the base of the cranium. 

The Sutures. 

The above bones are joined to each other by five sutures ; the 
names of which are the Coronal, Lambdoidal, Sagittal, and two 
Squamous. 

The coronal suture is extended over the head, from within about 
an inch of the external angle of one eye, to the like distance 
from the other ; which being near the place where the ancients 
wore their garlands, this suture has hence got its name. Though 
the indentations of this suture are conspicuous in its upper part, 
yet an inch or more of its end on each side has none, but is 
squamous and smooth. 

The lambdoidal suture begins some way below, and further 
back than the vertex or crown of the head, whence its two legs 
are stretched obliquely downwards, and to each side, in form of 
the Greek letter A, and are now generally said to extend them- 
selves to the base of the skull ; but formerly, anatomists reckoned 
the proper lambdoidal suture to terminate at the squamous su- 
tures : and the portion continued from them on each side, where 
the indentations are less conspicuous than in the upper part of 
the suture, they called additamentum sutura lambdoidis. 

This suture is sometimes very irregular, being made up of a 
great many small sutures, which surround a number of insulated 
bones, that are generally more conspicuous on the external sur- 
face of the skull than internally. These bones are commonly call- 
ed triquetra or wormiana ; their formation is owing to a greater 
than ordinary number of points of ossification in the skull, or to 
the ordinary bones of the cranium not extending their ossifica- 
tion far enough or soon enough ; in which case, the unossified in- 
terstice between such bones begins a separate ossification, in one 
or more points ; from which the ossification is extended to form 



THE SUTURES. - eg 

as many distinct bones as there were points which are extended 
into the large ordinary bones, and into each other.* 

The sagittal suture is placed longitudinally, in the middle of 
the upper part of the skull, and commonly terminates at the 
middle of the coronal and of the lambdoidal sutures; between 
which it is said to be placed, as an arrow is between the string 
and the bow. This suture is sometimes continued through the 
middle of the os frontis down to the root of the nose. 

The squamous agglutinations, or false sutures, are one on each 
side, a little above the ear, of a semicircular figure, formed by 
the overlapping (like one scale upon another) of the upper part 
of the temporal bones on the lower part of the parietal, where, 
in both bones, there are a great many small risings, and fur- 
rows which are indented into each other : though these inequali- 
ties do not appear until the bones are separated. In some skulls, 
indeed, the indentations here are as conspicuous externally as in 
other sutures ; and what is commonly called the posterior part of 
this squamous suture, always has the evident serrated form ; and 
therefore is reckoned by some a distinct suture, under the name 
of additamentum posterius suturae squamosa. 

The squamous suture is not confined to the conjunction of the 
temporal and parietal bones, but is made use of to join all the 
edges of the bones on which each temporal muscle is placed ; 
for the two parts of the sphenoidal suture, which are continued 
from the anterior end of the common squamous suture just now 
described, one of which runs perpendicularly downwards and 
the other horizontally forwards ; and also the lower part of the 
coronal suture already taken notice of, may all be justly said to 
pertain to the squamous suture. 

This structure appears to depend upon the pressure of the 
temporal muscle externally, and the resistance of the brain 
within, which makes the bones so thin, that their edges opposed 

* These ossa triquetra or wormiana are also frequently met with in the sagittal 
suture, and occasionally in all the different sutures of the cranium. As many as 
fifteen or twenty have been seen in a single head, though usually their number is 
much less. Where the cranium is of a globular form, few, and frequently none, 
are met with. They never begin to ossify till six months or a year after birth. — p. 



56 THE SUTURES. 

to each other are not sufficiently thick to stop the extension of 
their fibres in length, and thus to cause the common serrated ap- 
pearances of sutures; but the narrow edge of the one bone slides 
over the other. The squamous form is also more convenient 
here; because such thin edges of bones, when accurately ap- 
plied one to another, have scarce any rough surface, to obstruct 
or hurt the muscle in its contraction ; which is still farther pro- 
vided for, by the manner of laying these edges on each other ; 
for, in viewing their outside, we see the temporal bones covering 
the sphenoidal and parietal, and this last supporting the sphe- 
noidal, while both mount on the frontal, from which disposition it 
is evident, that while the temporal muscle is contracting, which 
is the only time it presses strongly in its motion on the bones, its 
fibres slide easily over the external edges. Another advantage 
of this structure is, that the whole part is made stronger by the 
bones thus supporting each other. 

The indentation of the sutures are not so strongly marked on 
the inside as on the outside of the cranium ; and sometimes the 
bones seemed to be joined by a straight line : in some skulls, the 
internal surface is found entire, while the sutures are manifest 
without. By this mechanism, there is no risk of the sharp points 
of the bones growing inwards, since the external serras of each 
of the conjoined bones rest upon the internal smooth-edged table 
of the other. 

The advantages of the sutures are these : 1. The cranium is 
more easily formed and extended into a spherical figure, than if 
it had been one continued bone. 2. The bones which are at some 
distance from each other at birth, may then yield, and allow to 
the head a change of shape, accommodated to the passage it is 
engaged in. Whence, in difficult parturition, the bones of the 
cranium, instead of being only brought into contact, are some- 
times made to mount one upon the other. 

[The sutures which unite the bones of the cranium, are gene- 
rally said to be made by the radii of ossification, from the op- 
posite bones meeting and passing each other, so as to form a ser- 
rated edge. This explanation is however insufficient, for the 
following reasons : we always find the sutures in the same rela- 



THE SUTURES. 



57 

tive situation, and observing the same course in the cranium ; if 
they, then, depended exclusively on so mechanical a process, as 
the shooting of the rays of bone across each other when they 
met, in ossification on one side of the head occurring sooner or 
faster than on the other, we ought to find the sagittal suture to 
one side of the middle line ; it should also, in many instances, be 
found crooked. Moreover, in all cases where bones arise from 
different points of ossification and meet, particularly in the flat 
bones, the serrated edges ought to be formed ; this, however, is 
not the case. The os occipitis, which is formed originally from 
four points of ossification, and has therefore as many bones com- 
posing it in early life, never joins these bones together by the ser- 
rated edge ; the acromion process of the scapula is never united 
to its spine by sutures ; the three bones of the sternum never 
unite by suture, and the same observation holds good in many 
other instances. Bichat, who rejects this mechanical doctrine, 
advances an opinion much better founded. The dura mater and 
the pericranium before ossification commences, form one mem- 
brane, consisting of two lamina ; it is generally known that the 
flat bones of the cranium are secreted between these two lamina ; 
now the outline of each bone, long before it has reached its ut- 
most limits, is marked off by partitions passing between these 
two membranes. The peculiar shape of the bony junction, or 
of the suture in adult life, will, therefore, depend upon the ori- 
ginal shape of the partitions : when the latter are serrated, the 
points of ossification will fill up these serras; but when they are 
simply oblique, the squamous suture will be formed. This also 
accounts for cases where the mode of junction is intermediate to 
the squamous and serrated suture ; for the formation of the ossa 
triquetra, and why in some skulls they do not exist, whereas in 
others their extent and number are very considerable. The in- 
ference will also be drawn from this, that in all ossifications from 
different nuclei, where these original membraneous septa do not 
exist, a suture will not be formed ; but the bones will join each 
other, as in a case of callus between the broken extremities of 
bones. When these septa become weak or thin, either from ori- 
ginal tendency, as in the case of the sagittal suture, which in 



58 



THE SUTURES. 



early life is continued to the root of the nose frequently ; or from 
advanced age, as in the case of nearly all sutures, the bones of 
the opposite sides amalgamate, and no appearance of suture is 
left. It is easy to make a preparation illustrative of these facts, 
and one now exists in the museum of the University of Pennsyl- 
vania, in which, by removing the bone from between the mem- 
branes by means of an acid, and afterwards rendering the mem- 
branes transparent with oil of turpentine, the septa are seen suf- 
ficiently distinctly.] 

Os Frontis. 

The os frontis, as its name imports, forms the front part of the 
cranium, and the upper portion of the orbits of the eyes. 

The external surface of this bone is smooth at its upper con- 
vex part; but several processes and cavities are observable be- 
low ; for at the angles of each orbit, the bone projects to form 
four processes, two internal, and as many external; which are 
denominated angular. Between the internal and external angu- 
lar processes on each side, an arched ridge is extended, on which 
the eyebrows are placed. Very little above the internal end of 
each of these superciliary ridges, a protuberance may be re- 
marked in most skulls, called the superciliary or nasal boss, 
where there are large cavities within the bone, called sinuses. 
Between the internal angular processes, and in front of the va- 
cuity for the ethmoid bone, the edge of the os frontis is serrated 
for articulation with the ossa nasi, and the process of the upper 
maxillary bone ; and from the centre of this surface a small pro- 
cess arises, which is called the nasal spine. From the under part 
of the superciliary ridges, the frontal bone runs a great way 
backwards : these parts are called orbitar processes, which, con- 
trary to the rest of this bone, are concave externally, for receiv- 
ing the globes of the eyes, with their muscles, fat, &c. 

In each of the orbitar processes, at the upper and outer 
portion of the orbit, a considerable sinuosity is observed, where 
the glandula lachrymalis is lodged. Near each internal angular 
process a small pit may be remarked, where the cartilaginous 
pulley of the superior oblique muscle of the eye is fixed. Be- 



OS FRONTIS. _ Q 



tween, the two orbitar processes, there is a large vacuity which 
the cribriform part of the os ethmoides occupies. The frontal 
bone has frequently little caverns formed in it where it is joined 
to the ethmoid bone. 

The foramina, or holes, observable on the external surface of 
the frontal bone, are three in each side. 

On each superciliary ridge, at the distance of one-third of its 
length from the nose, is a foramen, or a notch, through which 
pass a branch of the ophthalmic artery and a small nerve. 

In the internal edge of each orbitar process are two other 
foramina denominated anterior and posterior orbitar or ethmoidal 
foramina, which lead to the nose: sometimes they are only notches 
or grooves, which join with similar grooves in the bones below, 
and form foramina. They transmit the anterior and posterior 
ethmoidal arteries and veins, and the former transmits likewise 
the internal nasal branch of the ophthalmic nerve. 

The internal surface of the os frontis is concave, except at the 
orbitar processes, which are convex, and support the anterior 
lobes of the brain. This surface is not so smooth as the exter- 
nal; for the larger branches of the arteries of the dura mater 
make some furrows in its sides and back parts, and its lower 
and fore parts are marked with the convolutions of the anterior 
lobes of the brain. In the middle of the concave internal sur- 
face is a groove, which is small at its commencement, and gra- 
dually increases in diameter as it proceeds upwards. This is 
formed by the superior longitudinal sinus ; at its commencement 
is a ridge to which the beginning of the falciform process of the 
dura mater is attached. At the root of this ridge is a small 
foramen, sometimes formed jointly by this bone and the ethmoid; 
it is denominated foramen coecum; in it a small process of the 
falx is inserted, and here the longitudinal sinus begins. 

The frontal sinuses are formed by the separation of the two 
tables of this bone at the part above the nose and the internal 
extremities of the superciliary ridges. In the formation of these 
cavities, the external table commonly recedes most from the 
general direction of the bone. 

These cavities are divided by a perpendicular bony partition, 
which is sometimes perforated and admits a communication be- 



(JO OSSA PARIETALIA. 

tween them. Their capacities are often very different in differ- 
ent persons, and on the different sides of the same person. In 
some persons whose foreheads were very flat, they are said to 
have been wanting. They communicate with the nose by means 
of a canal in the cellular part of the os ethmoides. 

The os frontis is composed of two tables, and an intermediate 
diploe, as the other bones of the cranium are: it is of a mean thick- 
ness between the os occipitis and the parietal bones; and is nearly 
equally dense throughout, except at the orbitar processes, where, 
by the action of the eye on one side, and pressure of the lobes 
of the brain on the other, it is made extremely thin and diapha- 
nous, and the diploe is entirely obliterated. In this place there 
is so weak a defence for the brain, that fencers esteem a push in 
the eye mortal. 

In such skulls as have the frontal bone divided by the sagittal 
suture, the partition separating these cavities is evidently com- 
posed of two plates, which easily separate. 

Each of the frontal sinuses opens into one of the uppermost 
cells in the anterior part of the ethmoid bone, and this cell com- 
municates with the middle channel of the nose under the anterior 
end of the os turbinatum superius. 

This bone is united with the parietal, ethmoidal and sphenoi- 
dal bones of the head ; and with the nasal, maxillary, unguiform 
and malar bones of the face. 

Ossa Parietalia. 

Each of the two ossa parietalia is an irregular square; its 
upper and front edges being longer than the one behind or below. 
The inferior edge is concave, the middle part receiving the upper 
round part of the temporal bone. The angle formed by the 
under and anterior edges is so extended as to have the appear- 
ance of a process. 

The external surface of each os parietale is convex. Upon it, 
somewhat below the middle height of the bone, there is a trans- 
verse arched ridge, generally of a whiter colour than any other 
part of the bone; from which, in bones that have strong prints of 
muscles, we see a great many converging furrows, like so many 
radii drawn from a circumferc-"" *.?*"?_rr^ " — *" n "ev~™ ii^- 



OSSA PARIETALIA. 



61 



ridge of each bone the temporal muscle rises: and, by the pres- 
sure of its fibres, occasions the furrows just now mentioned. 
Below these we observe, near the semicircular edges, a great 
many risings and depressions, which are joined to like inequali- 
ties on the inside of the temporal bone, and form the squamous 
suture. Near the upper edges of these bones, towards the hind 
part, is a small hole in each, through which a vein passes from 
the teguments of the head to the longitudinal sinus.* 

On the inner concave surface of the parietal bones we see a 
great many deep furrows, disposed somewhat like the branches 
of trees : the furrows are largest and deepest at the lower edge 
of each os parietale, especially near its anterior angle, where 
a complete canal is sometimes formed. 

[These furrows are made by the ramifications of the great mid- 
dle artery of the dura mater : they have been commonly attri- 
buted to the pulsation of the artery causing the absorption of the 
bone, but it is more probable that the deposition of the bone 
has been prevented where the artery beats, and thus the bone 
becomes modelled over the artery in the same way that it is 
made to conform to the surface of the brain. If it were exclu- 
sively an absorption and not a deposition, we should scarcely 
find the artery occasionally surrounded perfectly by bone.] 

On the inside of the upper edge of the ossa parietalia there is 
a large sinuosity, frequently larger in the bone of one side than 
of the other, where the upper part of the falx is fastened, and 
the superior longitudinal sinus is lodged. Part of the lateral 
sinuses generally makes a depression near the angle formed by 
the lower and posterior edges of these bones; and the pits made 
by the convolutions of the brain are in no part of the skull more 
frequent or more conspicuous, than in the internal surface of 
these bones. 

The ossa parietalia are the most equal and smooth, and are 
among the thinnest bones of the cranium ; but they enjoy the 
general structure of two tables and diploe most perfectly. 

These bones are joined at their foreside to the os frontis, at 

* It transmits, also, an artery from the integuments to the dura mater, and is 
called the parietal foramen. — p. 

VOL. I. 6 



62 0SSA TEMPORUM. 

their long inferior angles, to the sphenoid bone ; at their lower 
edge, to the ossa temporum ; behind to the os occipitis, or ossa 
triquetra ; and above, to one another. 

Ossa Temporum.* 

The ossa temporum are situated at the lateral and inferior 
parts of the cranium ; each of them is divided into three portions, 
a superior or squamous, a posterior or mastoid, and a middle or 
petrous. 

The squamous portion is nearly semicircular in form, and very 
thin ; its edge is sharp, and the inner table appears pared away 
to form the squamous suture with the corresponding edge of the 
parietal bone. Its external surface is covered by the temporal 
muscle. At the lower and anterior part of this surface the zygo- 
matic process arises, it proceeds forward to join the cheek bone, 
and form an arch under which the temporal muscle passes. 

At the base of the process is the glenoid cavity for the condyle 
of the lower jaw. Immediately before this cavity is a tubercle 
or protuberance, which forms part of the articular surface on 
which the condyle rises when the jaw is opened. In the posterior 
part of the cavity is a fissure — called the glenoid — in which part 
of the ligament of this articulation is fixed. In this fissure is an 
aperture — glenoid foramen — which communicates with the ca- 
vity of the tympanum of the ear, and is occupied by a small 
nerve called chorda tympani ; and also by the anterior muscle 
of the malleus, one of the small bones of the ear. 

The internal surface of the squamous portion is concave; it 
is marked by pits and small eminences, which correspond with 
the convoluted surface of the brain, and also by impressions of the 
arteries of the dura mater, as they go towards the parietal bone. 

The mastoid or occipital portion is the smallest of the three 
parts of the bone; it consists of an angular portion, which occu- 
pies a vacuity between the occipital and parietal bones; and of 
the mastoid process. The mastoid process has some resemblance 

* This bone has received the name of temporal, because at the region which it 
covers, the hair usually commences to turn gray, and thus in some measure indi- 
cates the different periods of life. — p. 



OSSA TEMPORUM. go 

to the nipple ; it is composed internally of cells which communi- 
cate with the cavity of the tympanum. On the internal side of 
its base is a deep groove in which the posterior belly of the 
digastric muscle is inserted. Behind this process is the mastoid 
hole, which transmits a vein, and sometimes a small artery. 

On the internal surface of this portion is a large groove, which 
is formed by the lateral sinus. The mastoid hole above men- 
tioned, opens into this groove. 

The petrous portion, which is situated between the squamous 
and mastoid, resembles a triangular pyramid lying on one of its 
sides. When in its proper position it projects inward and for- 
ward. The two upper sides form a portion of the internal sur- 
face of the base of the cranium. The angle formed by these 
surfaces is very prominent, and divides the fossa from the middle 
lobes of the brain, or cerebrum from those which contain the 
cerebellum. 

One of these sides of the petrous portion looks forward and 
outward, the other backward and inward. Each of them has 
eminences and depressions to correspond with the convolutions 
of the brain. Near the middle of the anterior side is a small 
furrow, and a foramen denominated Jnnominatum or Hiatus 
Fallopii, which transmits the vidian nerve to the aqueduct of 
Fallopius. 

About the middle of the posterior side is the large aperture 
called meatus auditorius internus. The bottom of this cavity is 
perforated by several foramina; the largest and uppermost of 
which is the orifice of a winding canal, called improperly the 
aqueduct of Fallopius, which transmits the portio dura of the 
seventh pair of nerves. The other foramina transmit the fibres 
of the portio mollis of the same nerve. Posterior to the orifice 
of the meatus internus is an oblong depression, with a foramen 
in it, covered by a shell of bone, which is the orifice of a proper 
aqueduct or canal that passes from the vestibule of the ear.* 

The inferior side of the petrous portion forms a part of the ex- 
ternal surface of the basis of the cranium. On the back part of 

* This orifice should not be confounded with one which is nearer to the meatus 
internus, and situated on the angle made by the two sides of the bone. — h. 



64 OSSA TEMPORUM. 

it is the external orifice of the canal, through which the portio 
dura passes. It is called foramen stylo mastoideum. Before this 
foramen is a long and slender styloid process, which varies from 
one to two inches in length ; it projects almost perpendicularly 
from the basis of the cranium, and gives origin to a muscle of 
the tongue, of the os hyoides, and of the pharynx, and also to 
several ligaments. [The base of this process is surrounded by 
a flat projection of bone, occasionally called the vaginal process. 

On the inside of this process, and rather before it, is the jugu- 
lar fossa, which, when applied to a corresponding part of the 
occipital bone, makes the posterior foramen lacerum, through 
which the internal jugular vein, and the eighth pair of nerves 
pass out. A small spine often projects into this foramen from 
the temporal bone, and separates the nerve from the vein ; the 
nerve being anterior. Before this spine, or partition, is the 
orifice of the second aqueduct of the ear, the aqueduct of the 
cochlea. This jugular fossa is at the termination of the groove, 
in the internal surface of the bone, made by the lateral sinus. At 
a small distance before the jugular fossa is the commencement 
of the carotid canal, which makes a curve almost semicircular, 
and then proceeds in a horizontal course to the anterior extre- 
mity of the bone : through this winding canal passes the carotid 
artery, and the filaments from the fifth and sixth pair of nerves, 
which are the beginning of the intercostal nerve. 

Between the carotid canal and the cavity for the condyle of 
the lower jaw, at the junction of the anterior part of the squam- 
ous portion with the petrous portion of this bone, is a very rough 
aperture, the bony margin of which appears broken ; this is the 
orifice of the bony part of the Eustachian tube, or passage from 
the throat to the ear. This canal is divided lengthwise by a 
thin bony plate ; the upper passage contains the internal muscle 
of the malleus bone of the ear ; the lower and largest canal is 
the bony part of the Eustachian tube. 

The external passage to the ear, called Meatus Auditorius Ex- 
ternus, is situated between the zygomatic and the mastoid pro- 
cesses. The orifice is large and smooth above, but rough below, 



OS OCCIPITIS. 



65 



and is sometimes called the auditory process. The direction of 
the canal is obliquely inward and forward. 

The temporal is articulated with the parietal, occipital and 
sphenoidal bones, and by its zygomatic process with the malar 
bone. 

Os Occipitis. 

The occipital bone is situated at the posterior and inferior part 
of the cranium ; it is of a rhomboidal figure, with convex and 
concave surfaces. 

The upper part of the external surface is smooth : at a small 
distance above the middle of the bone is the external occipital pro- 
tuberance, with a curved line on each side of it. Near the middle 
of the bone the trapezii muscles are attached to this line, and 
externally, on each side, the occipito frontalis, and the sterno 
mastoideus. Under this line is a depression, on each side, into 
which are inserted the complexus and the splenius capitis muscles. 

Below this is the inferior curved line, and still lower is a mus- 
cular depression to which the rectus minor posticus is attached 
on each side near the middle ; and the rectus major, and obliquus 
superior, near the end. 

Below the protuberance is a spine which passes down the mid- 
dle of the bone, and at the lower extremity of this spine is the 
great occipital foramen, which forms the communications be- 
tween the cavities of the cranium, and the vertebral column. 
This great opening transmits the medulla spinalis with its mem- 
branes, the accessory nerves of Willis, and the vertebral arte- 
ries and veins. 

It is rather of an oval form, and the occipital condyles are 
situated anteriorly on its edges. These condyles are of an irre- 
gular oval figure ; they are not parallel, but incline towards each 
other anteriorly. Their articulating surfaces are oblique, look- 
ing downward and outward ; they are received into correspond- 
ing cavities of the atlas, or first cervical vertebra, and form with 
them the articulation of the head and neck. From the oblique 
position of their articulating surfaces, as well as the length of 
their ligaments and the inclination of their axes towards each 
other, it results, that their motion is confined to flexion and ex- 

6* 



66 os occipitis. 

tension. On the internal sides of these condyles is a rough sur- 
face, to which are attached the strong ligaments that come from 
the processus dentatus of the second vertebra of the neck. 

Behind each condyle is a depression in which is situated the 
posterior condyloid foramen, for transmitting the cervical veins; 
and at their anterior extremities are two large foramina, (anterior 
condyloid,) through which pass the ninth pair of nerves. 

On the internal surface of the os occipitis is the crucial ridge, 
to which are attached the falx or vertical, and the tentorium, or 
horizontal process of the dura mater. 

The groove made by the longitudinal sinus continues from the 
sagittal suture along the upper limb of this cross. Sometimes it 
is on the side of the ridge, and sometimes the ridge is depressed, 
and it occupies its place ; at the centre of the cross, the groove 
for the longitudinal sinus divides into two grooves, for the lateral 
sinuses ; these form the horizontal limbs of the cross, and pro- 
ceed towards the foramen lacerum where the lateral sinuses 
emerge from the cavity of the cranium. The lower limb of the 
cross is formed by a spine which proceeds from the centre to the 
great occipital foramen, and supports the falx of the cerebellum. 
The internal surface of the bone is divided by the cross into four 
portions, each of which is considerably depressed ; the two up- 
per by the posterior lobes of the cerebrum, and the lower by 
those of the cerebellum. 

This circumstance occasions great inequality in the thickness 
of the bone, as the depressed portions are extremely thin, while 
the ridge adds greatly to the thickness, especially at the centre 
of the cross, which is opposite to the great external protu- 
berance. 

Before the great occipital foramen is the cuneiform process, 
which is thick and substantial; it terminates by abroad truncated 
extremity, which is articulated with the body of the sphenoid 
bone. The internal surface of the cuneiform process is some- 
what excavated, and forms a large superficial groove for the 
medulla oblongata; on each side of this groove is a small furrow 
for the inferior petrous sinuses. 

The two upper edges of the occipital bone are serrated, to 



OS ETHMOIDES. 



67 



articulate, with those of the parietal, and form the lambdoidal 
suture. The inferior edges are divided into two portions by a 
small prominence called the jugular eminence ; the upper and 
posterior portion is also serrated for articulation with the mas- 
toid portion of the temporal ; the inferior portion, which is not 
serrated, applies to the petrous portion of the temporal bone, 
and a notch in it contributes to the formation of the foramen 
lacerum. 

The upper angle of this bone is acute, the lateral angles are 
obtuse, and the inferior truncated. It is articulated with the pa- 
rietal, the temporal, and the sphenoidal bones. 

Os Ethmoides. 

The os ethmoides is truly one of the most curious bones of the 
human body. It appears almost a cube, not of solid bone, but 
exceedingly light and spongy, and consisting of many convoluted 
plates, which form a network like honey-comb. It is firmly 
enclosed in the os frontis, betwixt the orbitary processes of that 
bone. One horizontal plate receives the olfactory nerves, which 
perforate that plate with such a number of small holes, that it 
resembles a sieve ; whence the bone is named cribriform, or eth- 
moid. Other plates are so arranged that they form a cellular 
structure, on which the olfactory nerves are expanded by means 
of a particular membrane; while an additional plate, appropria- 
ted to the nose, descends into that cavity in a perpendicular di- 
rection, and forms a large proportion of the partition which 
divides it into two chambers. 

The cribriform plate is situated in the anterior part of the 
basis of the cranium. The cellular part occupies most of the 
space between the orbits of the eyes, and the perpendicular plate 
is to be found in the septum of the nose. 

The ethmoid bone, for the purposes of description, may be di- 
vided into three parts, viz. the cribriform plate, the nasal or per- 
pendicular lamella, and the cellular portions. 

The cribriform plate is oblong in shape, and firm in its struc- 
ture; in the middle of the anterior extremity the crista galli pro- 
jects from its upper surface, dividing it into two lateral portions, 



68 OS ETHMOIDES. 

each of which is rather concave, and occupied by the bulbous 
extremity of the olfactory nerve ; it is perforated by many fora- 
mina, which transmit the fibres of the aforesaid nerve. Near 
the crista galli, on each side, there is a small fissure, through 
which passes a nervous filament derived from the ophthalmic 
branch of the fifth pair. The crista galli varies in size in dif- 
ferent subjects : the beginning of the falciform process of the 
dura mater is attached to it, and with the opposite part of the os 
frontis it forms the foramen caecum, already mentioned. It is 
very conspicuous in the basis of the cranium. 

The nasal plate of the ethmoid bone seems to be continued 
downwards from the crista galli through the cribriform plate. It 
is thin, but firm ; it forms the upper portion of the septum of the 
nose, and, to complete the partition, it unites with the vomer and 
with a plate of cartilage before. It is very often inclined to one 
side, so that the nostrils are not of equal size. 

At a small distance from this perpendicular plate, on each side 
of it, the cellular portions originate from the lower surface of 
the cribriform plate ; they extend from before backward, and 
are as long as the ethmoid bone; their breadth between the eye 
and the cavity of the nose varies in different subjects, from half 
an inch to more ; they extend downwards from the root of the 
nose or from the cribriform plate, more than half way to the 
roof of the mouth. Their external surface on each side forms a 
part of the surface of the orbit of the eye, and is called os pla- 
num; their internal surface forms part of the external lateral 
surface of each nostril. This surface extends the whole depth 
of the nostril, from before backward ; but in many skeletons it is 
extremely imperfect, owing to the great brittleness of the bony 
plates of which it is composed. When the bone is perfect, the 
uppermost half part of this internal surface is uniformly flat, and 
rather rough ; but below it, about the middle of the bone, a deep 
groove begins, which extends downwards and backwards, to 
the posterior extremity ; this is the upper channel or meatus of 
the nose. The edge of the surface immediately above it projects 
in a small degree over this channel or groove ; having been de- 
scribed by Morgagni, it bears his name, and mav be considered 



OS ETHMOIDES. 



69 

as one of the spongy or turbinated bones ; from its situation, it 
should be called the first. The groove is very deep, and most 
of the cells of the posterior part of the ethmoid bone communicate 
with it, through one or more foramina at its anterior extremity. 

The part of the surface of the ethmoid which is immediately 
below this groove, is convex ; that which is before and below it, 
is rather flat ; the convex part is the upper spongy or turbinated 
bone, as it has commonly been called ; it projects obliquely into 
the cavity of the nose, and hangs over the middle channel or 
meatus, which is immediately below the ethmoid bone. The in- 
ternal surface of this spongy bone, which is opposite the septum 
of the nose, is convex and rough or spongy ; the external surface 
is concave. The anterior cells of the ethmoid, and particularly 
those which the frontal sinuses on each side communicate with, 
open into the middle channel or meatus, under the anterior end 
of this turbinated bone. 

This middle channel ormeatus, is much larger than that above ; 
it extends from the anterior to the posterior part of the nostrils, 
and slope* downwards and backwards. The cavity of the up- 
per maxillary bone, or the antrum highmorianum, opens on 
each side into this meatus, and a thin plate of bone extends from 
the cellular part of the ethmoid so as to cover a part of it. 

The cellular portions of the ethmoid are composed of plates 
thinner than the shell of an egg ; they are entirely hollow, and 
the cells are very various, in number, size, and shape. Some 
cells of the uppermost row communicate with those of the os 
frontis, formed by the separation of the plates of the orbitar pro- 
cess of that bone. 

From the posterior part of the cribriform plate, where it is 
in contact with the lesser wings of the sphenoidal bone, thin 
plates of bone pass down upon the anterior surface of the body 
of the os sphenoides, one on each side of the azygos process, 
and often diminish the opening into the sphenoidal cells. These 
plates are sometimes triangular in form, the bases uniting with 
the cribriform plate. They have been described very differently 
by different authors, some considering them as belonging to the 



70 OS ETHMOIDES. 

os ethmoides, and others to the sphenoid bone. To the perfect 
ethmoid bone there are attached two triangular pyramids, in 
place of the triangular bones; these pyramids are hollow, the 
azygos process of the os sphenoides is received between them ; 
one side of each pyramid applies to each side of the azygos pro- 
cess, another side applies to the anterior surface of the body of 
the sphenoid bone, in place of the ossa triangularia, and the third 
side is the upper part of one of the posterior nares.* There are 

* This may be considered as an original observation of the lamented Wistar. 
The merit of it has been denied to him, more particularly by the anatomists of 
Paris, under an impression that he had been anticipated in it by Bertin, who has 
written an excellent and minute treatise on osteology. The extent to which the 
claims of other anatomists interfere with his, he was fully aware of; and it will be 
seen by the following communications to the American Philosophical Society, that 
these are placed in as important a light as they deserve, at the same time that he 
vindicates his own pretensions, to have first observed the " cornets sphenoidaux" in 
the form of triangular hollow pyramids, as constituting part of the perfect ethmoid 
bone. — h. 

Observations on those Processes of the Ethmoid Bone which originally form the 
Sphenoid Sinuses. By C. Wistar, M. D. President of the Society \ Professor of 
Anatomy in the University of Pennsylvania. — Read, Nov. 4, 1814. 
It has been long believed that the sinuses, or cavities in the body of the os 
sphenoides, were exclusively formed by that bone, when Winslow suggested that 
a small portion of the orbitar processes of the ossa palati contributed to their for- 
mation.* 

Many years after Winslovv's publication, Monsieur Bertin described two bones 
which form the anterior sides of these sinuses, and contain the foramina by which 
they communicate with the nose.t 

These bones he denominates " Cornets Sphenoidaux," and states that they are 
most perfect and distinct between the ages of four years and of twenty ; that they 
are not completely formed before this period, and that after it they appear like a 
part of the sphenoidal bone. — According to his account they are lamina of a tri- 
angular form, and are originally in contact with the anterior and inferior surface 
of the body of the os sphenoides, so that they form a portion of the surface of the 
cavity of the nose. — He believed, that as they increase in size, they become convex 
and concave, and present their concave surfaces to the body of the sphenoidal 
bone, which also becomes concave, and presents its concavity to those bones; thus 
forming the sinuses. 

* In his description of the Ossa Palati, printed in the Memoirs of the Academy of Sciences 
for 1720. 

f See Memoirs of the Academy of Sciences for 1774. 



03 SPHENOIDES. ~j 

two apertures in each of these pyramids ; one at the base open- 
ing directly into the nose, near the situation of the opening of the 

This account of M. Berlin has been adopted by Sabatier, and also by Boyer, 
who has improved it by the additional observation, that these triangular bones are 
sometimes united to the ethmoid, and remain attached to that bone when it is sepa- 
rated from the os sphenoides. Bichat and Fyfe have confirmed the description of 
Boyer. 

The specimens of ethmoid and sphenoid bones, herewith exhibited to the so- 
ciety, will demonstrate that in certain subjects, about two years of age, there are 
continued from the posterior part of the cribriform plate of the ethmoid, two Hol- 
low Triangular Pyramids, which, when in their proper situations, receive between 
them the azygos process of the os sphenoides. — (See Plate X. Figures 1, 2, 3, 
with the explanation.) 

The internal side of each of these pyramids applies to the aforesaid azygos pro- 
cess ; the lower side of each forms part of the upper surface of the posterior 
nares ; the external side at its basis is in contact with the orbitar process of the 
os palati. The base of each pyramid forms also a part of the surface of the 
posterior nares, and contains a foramen which is ultimately the opening into the 
sphenoidal sinus of that side. 

In the sphenoidal bones, which belong to such ethmoids as are above described, 
there are'no cells or sinuses ; for the pyramid of the ethmoid bones occupy their 
places. The azygos process, which is to become the future septum between the 
sinuses, is remarkably thick, but there are no cavities or sinuses in it. 

The sides of the pyramids, which are in contact with this process, are extremely 
thin, and sometimes have irregular foramina in them, as if their osseous substance 
had been partially absorbed.* That part of the external side of the pyramid 
which is in contact with the orbitar process of the os palati is also thin, and some- 
times has an irregular foramen, which communicates with the cells of the aforesaid 
orbitar process. 

Upon comparing these perfect specimens of the ethmoid and sphenoidal bones 
of the subject about two years of age, with the os sphenoides of a young subject 
who was more advanced in years, it appears probable that the azygos process and 
the sides of the pyramid applied to it, are so changed, in their progress of life, that 
they simply constitute the septum between the sinuses ; that the external side of 
the pyramid is also done away, and that the front side and the basis of the pyra- 
mid only remain ; constituting the Cornets Sphenoidauxt of M. Bertin. 

If this be really the case, the origin of the sphenoidal sinuses is very intelligible. 

* See e, Fig. 3. 

t "Comet" is the word applied by several French anatomists to the Ossa Turbinati of the 
nose ; they seem to have intended to express by it a convoluted lamina or plate of bone. 

The fine drawing of the Ethmoid Bone, for this plate was done by my friend M. Lesueur. 
whose talents are so conspicuous in the plates attached to Peron's " Voyage de Descouvertes 
aux Terres Australes." 



72 OS SPHENOIDES. 

sphenoidal sinuses, in the bones of adults; and the other in each 
of the sides in contact with the azygos process. 

Os Sphenoides. 

The os sphenoides or pterygoideus, resembles a bat with its 
wings extended. It consists, 

1st. Of a body with two processes arising from it, called the 
lesser wings, or apophyses of Ingrassias. 

2dly. Of two large lateral processes, called the greater wings, 
or temporal processes ; and, 

3dly. Of two vertical portions, denominated pterygoid pro- 
cesses. 

The body is situated near the centre of the cranium, and in con- 
tact with the cuneiform process of the occipital bone ; the greater 
wings extend laterally between the frontal and temporal bones 
as high as the parietal ; while the pterygoid processes pass down- 

Explanalion of the Figures in the Plate referred to above. 
FIG. I. 
Represents the upper surface, or cribriform plate of the Ethmoid Bone. 
a. Crista Galli. 
b b b b. Cribriform plate, 
c. Surface denominated Os Planum. 
d d. Hollow Triangular Pyramids. 

e. Space between the Pyramids for receiving the Azygos Process of the Os Sphe- 
noides. 

FIG. II. 

A lateral View of the Bone. 
a. Crista Galli. 

c. Os Planum. 

d. Triangular Pyramid. 

FIG. III. 
The Bone Inverted. 
a. The Nasal Plate of the Ethmoid Bone, which constitutes the upper portion 

of the Septum of the nose. 
g g. Those portions of the Ethmoid which are called Superior Turbinated 

Bones. 
//. The Cellular Lateral Portions of the Bone. 
d d. The Triangular Pyramids. 

e. Space between the Pyramids for the Azygos Process of the Os Sphenoides— 
a foramen on the internal side of one of the Pyramids. 









v 



i 



< ""- : \ 



^^■^ 



.is 



^ 




'■* 






& 










^ 



. S 
"* -i 2 - 



S 



OS SPHENOIDES. 



73 



wards on each side of the posterior opening of the nose, as low 
as the roof of the mouth. It is, therefore, in contact with all 
the other bones of the cranium, and with many bones of the 
face. 

The body has a cubic figure, its upper surface forms a portion 
of the basis of the cranium; its lower and anterior surfaces 
form part of the cavity of the nose ; the posterior surface is arti- 
culated with the cuneiform process of the occipital bone ; and 
laterally it is extended into the great wings, or temporal pro- 
cesses. 

On the upper surface of the body, the lesser wings or the 
apophyses of Ingrassias,* project from the lateral and anterior 
parts; these wings consist of two triangular plates, each of 
which is joined to the other by its base, and to the body of the 
os sphenoides by its under surface near the base, and terminates 
in a point; their direction is forwards and outwards, and their 
flat surfaces are horizontal. Anteriorly they are connected by 
suture to the ethmoid and frontal bones; their posterior edge is 
rounded, and detached from any other bone, forming the upper 
margin of the foramen lacerum of the orbit of the eye ; this 
edge is thick and prominent at its internal extremity, and these 
prominences are called the anterior or clinoid processes ; imme- 
diately before them are the optic foramina, which pass obliquely 
through the wings into the orbit of the eye, and transmit on each 
side the optic nerve and a small artery. 

Behind the optic foramen is a notch and sometimes a foramen, 
made by the carotid artery. A groove made by the optic nerves, 
is often seen extending across the body of the bone, from one of 
the optic foramina to the other. Behind it is a depression, which 
occupies the greatest part of this surface of the bone, in which 
the pituitary gland is lodged ; the back part of this depression is 
bounded by a transverse eminence, called the posterior clinoid 
process. These three processes are called clinoid from their 
supposed resemblance to the supporters of a bed ; and the de- 
pression for the pituitary gland is called cella turcica from its 
resemblance to the saddle used by the Turks. 

* A physician of Palermo, who died in 1580, aged 70. — h. 
VOL. I. 7 



74 OS SPHENOIDES. 

On each side of the posterior clinoid process is a groove in 
the body of the bone, made by the carotid artery as it passes 
from the foramen caroticum of the temporal bone. The poste- 
rior surface of the body of the sphenoides is rough, for articula- 
tion with the truncated end of the cuneiform process of the os 
occipitis. 

On the anterior and inferior surfaces is a spine, called the 
azygos process, which is received into the base of the vomer, 
and extends forward until it meets the nasal plate of the ethmoid 
bone ; on each side of this spine, in the anterior surface, are the 
orifices of the sphenoidal cells. Those orifices appear very dif- 
ferently in different bones; in some very perfect specimens, they 
are irregularly oval, being closed below, and on their external 
sides, by the processes of the ossa palati, and above by the tri- 
angular plates, as they have been called, of the ethmoid bone. 
The cells or sinuses, to which these orifices lead, occupy the 
body of the sphenoidal bone ; they are divided by a partition, 
and each of them has a communication with the cavity of the 
nose on its respective side, by the orifice above described. The 
sinuses do not exist during infancy; they increase in the pro- 
gress of life, and are very large in old age. 

Laterally, the body of the sphenoides is extended into the por- 
tions called the great wings or temporal processes. These great 
wings compose the largest part of the bone, and their internal 
surface forms a portion of the middle fossa of the base of the 
cranium. Externally, the surface of each great wing is divided 
into two portions: one of which is lateral, and unites to the fron- 
tal, temporal, and malar bones, forming part of the smooth sur- 
face for the temporal muscle ; the other portion forms part of 
the orbit of the eye, and is very regular and smooth. As the 
ethmoid bone forms part of the inside, this portion of the great 
wing forms part of the outside of the orbit, and is termed the 
orbitary process of the sphenoid bone. The horizontal part of 
each wing terminates in an acute angle termed spinous process, 
which penetrates between the petrous portion and the articulat- 
ing cavity of the temporal bone. In this angle is the foramen 
for the principal artery of the dura mater ; near the point of the 



FORAiMINA OF THE SPHENOIDAL BONE. 75 

angle is a small process, which projects from the basis of the 
cranium, and is called styloid. 

The pterygoid processes pass downwards in a direction almost 
perpendicular to the base of the skull. Each of them has two 
plates, and a middle fossa facing backwards; to complete the 
comparison, they should be likened to the legs of the bat, but 
are inaccurately named pterygoid, or wing-like processes. The 
external plates are broadest, and the internal are longest. From 
each side of the external plates the pterygoid muscles take their 
rise. At the root of each internal plate, a small hollow may be 
remarked, where the musculus circumflexus palati rises, and part 
of the cartilaginous end of the Eustachian tube rests. At the 
lower end of the plate is a hook-like process, round which the 
tendon of the last named muscle plays, as on a pulley. The 
ossa palati, on each side, rest upon these internal plates ; and, 
therefore, the pterygoid processes seem to support the whole 
face. 

Foramina of the Sphenoidal Bone. 

Before these foramina are described, it is necessary to state, that the nerves of the 
brain are named numerically, beginning with the olfactory, which is foremost. 

It should also be observed, that each nerve of the fifth pair is divided, before it 
passes from the cavity of the cranium, into the three large branches. 

The first foramina are the optic, which have been already 
described ; they transmit the optic, or second pair of nerves, and 
a small artery, to the ball of the eye. 

The second foramen, on each side, is the foramen lacerum. It 
commences largely at the cella turcica, and extends laterally a 
considerable distance, until it is a mere fissure. The upper 
margin of this foramen is formed by the anterior clinoid pro- 
cesses, and the edges of the smaller wings of the sphenoid bone. 
This foramen transmits the third, fourth, and sixth pair of nerves, 
and the first branch of the fifth pair, to the muscles, and the 
other parts, subservient to the eye. 

The foramen rotundum, or third hole, is round ; as its name 
imports. It is situated immediately under the foramen lacerum, 



76 THE FACE. 

on each side, and transmits the second branch of the fifth pair 
of nerves to the upper maxillary bone. 

The foramen ovale is the fourth hole. It is larger than the 
foramen rotundum, and half an inch behind it. It transmits the 
third branch of the fifth pair of nerves to the lower jaw. 

The fifth hole is the foramen spinale. It is small and round, 
and placed in the point of the spinous process, behind the fora- 
men ovale, to transmit the principal artery of the dura mater, 
which makes its impression upon the parietal bone. 

The sixth foramen is under the basis of each pterygoid pro- 
cess, and is therefore called the pterygoid, or the Vidian* foramen. 
It is almost hidden by the point of the petrous portion of the 
temporal bone, and must be examined in the separated bone. It 
is nearly equal in size to the spinous hole. 

This foramen transmits a nerve that does not go out from the 
cavity of the skull, but returns into it. The second branch of 
the fifth pair, after passing out of the cranium, sends back, 
through this foramen, a branch called the Vidian, which upon 
its arrival in the cavity of the cranium, enters the temporal bone 
by the foramen innominatum. 

Of the Face. 

The face is the irregular pile of bones composing the front 
and under part of the head, and is divided into the upper and 
lower maxillae, or jaws. 

The upper jaw consists of six bones on each side, of one single 
bone placed in the middle, and of sixteen teeth. 

The thirteen bones are, two ossa maxillaria superiora, two 
ossa nasi, two ossa unguis, two ossa malarum, two ossa palati, 
two ossa spongiosa inferiora, and the vomer. 

The ossa maxillaria superiora form the principal part of the 
cavity of the nose, with the whole lower and forepart of the up- 
per jaw, and a large proportion of the roof of the mouth. 

The ossa nasi are placed at the upper and front part of the 
nose. 

* From its reputed discoverer, Vidius, a professor at Paris. 



OSSA MAXILLARIA SUPERIORA. 77 

The ossa unguis are at the internal angles of the orbits of the 
eyes. 

The ossa palati in the back part of the palate, extending up- 
wards to the orbits of the eyes. 

The ossa spongiosa in the lower part of the cavity of the nose; 
and 

The vomer in the partition which separates the two nostrils. 

Ossa Maxillaria Superiora. 

The ossa maxillaria superiora, or upper jaw bones, may be 
considered as the basis or foundation of the face ; as they form 
a large part of the mouth, the nose, and the orbit of the eye. 

The central part of each bone, which may be considered as 
its body, is hollow, and capable of containing, in the adult, near 
half an ounce of fluid. The plate which covers this cavity is 
the bottom of the orbit of the eye. The sockets of the large 
teeth are below it. The roof of the mouth projects laterally 
from the inside of it. A process for supporting the cheek bone 
is on the outside ; and another process goes up before it, which 
forms the side of the nose. 

In each upper maxillary bone the following parts are to be 
examined : 

The nasal process ; the orbitar plate ; the malar process ; the 
alveolar process; the palatine process; the anterior and posterior 
surfaces ; the great cavity ; the internal or nasal surface ; and 
the three foramina. 

The nasal process, which extends upwards to form the side of 
the nose, is rather convex outwards, to give the nostril shape. 
Its sides support the nasal bone ; and a cartilage of the alse nasi 
is fixed to its edge. 

The margin of the orbit of the eye is marked by a sharp ridge 
on the external surface of this process ; and the part posterior 
to this ridge is concave to accommodate the lachrymal sac. 

The orbitar plate, which covers the great cavity, and forms 
the bottom of the orbit, is rather triangular in form, and con- 
cave. In the posterior part is a groove, which penetrates the 
substance of the bone, as it advances forward, and terminates in 

7* 



78 OSSA MAXILLARIA SUPERIOR A. 

the infra-orbitary foramen, below the orbit. At the place where 
this plate joins the nasal process above mentioned, viz. at the 
inner angle of the orbit, is the commencement of the bony canal, 
which transmits the lachrymal duct into the cavity of the nose. 

The malar process projects from the external and anterior 
corner of the orbitar plate ; it supports the malar bone, and is 
rough for the purpose of articulating with it. 

The alveolar processes compose the inferior and external mar- 
gins of the upper maxillary bones. When these bones are applied 
to each other, they form more than a semicircle : their cavities 
contain the roots of the teeth, and correspond with them in size 
and form. They do not exist long before the formation of the 
teeth commences ; they grow with the teeth ; and when these 
bodies are removed, the alveoli disappear. 

The palate process is a plate of bone, which divides the nose 
from the mouth, constituting the roof of the palate, and the floor 
or bottom of the nostrils. It is thick where it first comes off from 
the alveolar process ; it is thin in its middle ; and it is again thick 
where it meets its fellow of the opposite side. At the place 
where the two upper jaw bones meet, the palate plate is turned 
upwards, so that the two bones are opposed to each other in the 
middle of the palate, by a broad flat surface, which cannot be 
seen but by separating the bones. This surface is so very rough, 
that the middle palate suture almost resembles the sutures of the 
skull; and the maxillary bones are neither easily separated, nor 
easily joined again. The meeting of the palate plates by a broad 
surface, makes a rising, or sharp ridge, towards the nostrils ; so 
that the breadth of the surface by which these bones meet, serves 
a double purpose ; it joins the bones securely, and it forms a 
small ridge upon which the edge of the vomer or partition of the 
nose, is planted. Thus we find the palate plates of the maxillary 
bones conjoined, forming almost the whole of the palate ; while 
what are properly called the palate bone forms a very small 
share of the back part only. As these thinner bones of the face 
have no medulla, they are nourished by their periosteum only, 
and are of course perforated with many small holes. 

The anterior surface of the upper maxillary bone is concave; 



OSSA MAXILLARIA SUPERIORA. 



79 



the margin formed by the lower edge of the orbit, by the malar 
process, and by the alveolar processes, being more elevated than 
the central part. At a small distance below the orbit is the infra- 
orbitary foramen for transmitting a branch of the superior maxil- 
lary nerve. When these two bones are applied to each other, 
and the ossa nasi are in their places, they form the anterior ori- 
fice of the nasal cavity, which has a small resemblance to the 
inverted figure of the heart on cards. 

The posterior surface has been called a process or tuber. It 
expands to a considerable size, and is united internally and poste- 
riorly to the ossa palati. The great cavity extends from the bot- 
tom of the orbit of the eye to the roof of the mouth, and from 
the anterior to the posterior surface of the bone ; it opens in the 
cavity of the nose, and is called antrum maxillare, or Highmo- 
rianum.* There is but a small portion of bone between this 
cavity and the sockets of the teeth, particularly those of the 
second malar tooth. 

The internal or nasal surface of this bone forms a large part 
of the cavity of the nose, and is concave. At the root of the 
nasal process is a ridge, for supporting the anterior end of the 
lower turbinated bone. The nasal process seems continued into 
the cavity of the nose, and forms a portion of the orifice of the 
canal for the lachrymal duct, which is on the external side of 
this cavity, near its anterior opening, and under the lower turbi- 
nated bone. The orifice in this bone by which the antrum max- 
illare communicates with the nose, is very large; but it is re- 
duced to a small size, by a plate from the ethmoid bone, by a 
portion of the ossa palati, and of the lower spongy bone, each of 
which covers a part of it. 

The three foramina are, 1st. The infra-orbitary foramen al- 
ready described. 2d. The foramen incisivum or anterior pala- 
tine hole, which passes through the palatine process, from the 
nose to the mouth. In the nose there are generally two fora- 
mina, which unite and form but one in the mouth, immediately 
behind the middle incisor teeth. This foramen is closed by the 
soft parts during life, and transmits a branch of the spheno-pala- 

* After an anatomist who described it. 



8Q OSSA NASI. 

tine nerve from each side which runs on the septum narium, and 
joining at the lower part of the canal with its fellow, they unite, 
and, according to M. Cloquet, form a ganglion. 3d. The pos- 
terior palatine foramen, which is formed by this bone, and by the 
os palati, on each side, is situated in the suture which joins them 
to each other, and transmits to the palate a branch of the upper 
maxillary nerve. 

This bone is united to the frontal, nasal, unguiform, ethmoid 
and malar bones, above; to the ossa palati behind; to the corre- 
sponding bone, on the opposite side; and to the inferior spongy 
bone, in the cavity of the nose. 

Ossa Nasi. 

The ossa nasi are so named from their prominent situation at 
the root of the nose. They are each of an irregular oblong 
figure, being broadest at their lower end, narrowest near the 
middle, and larger again at the top, where the edge is rough and 
thick, and their connexion with the os frontis is consequently 
very strong. They are convex externally, and concave within. 
The lower edges of these bones are thin and irregular. Their 
anterior edges are thick, and their connexion with each other, by 
means of their edges, is firm ; the suture between them, extending 
down the middle of the nose, forms a prominent line on the in- 
ternal surface, by which they are united to the septum narium. 
The uppermost half of their posterior edges is covered by the 
edges of the nasal processes of the upper maxillary bones ; the 
lower half laps over the edges of these bones ; and by this struc- 
ture they are enabled to resist pressure. [On the posterior sur- 
face of the os nasi is a groove occupied in the recent subject by 
a branch of the ophthalmic nerve called the nasal, which enters 
the nose through the foramen orbitare internum anterius.] They 
are joined above to the os frontis; before, to each other; behind, 
to the upper maxillary bones ; below, to the cartilages ; and in- 
ternally, to the septum of the nose. 

Ossa Unguis. 

The ossa unguis are so named from their resemblance to a 
nail of the finger. They are situated on the internal side of the 



OSSA UNGUIS. 



81 

orbit of the eye, between the os planum of the ethmoid, and the 
nasal process of the upper maxillary bone. Their external sur- 
face is divided into two portions, by a middle ridge ; the posterior 
portion forms part of the orbit ; and the anterior, which is very 
concave, forms part of the fossa, and canal, for containing the 
lachrymal sac and duct. This portion is perforated by many 
small foramina; and the whole, being extremely thin and brittle, 
is therefore often destroyed by the preparation of the subject. 

The internal surface of this bone is generally in contact with the 
cells of the ethmoid ; a small portion of the anterior parts is in 
the general cavity of the nose. Each os unguis is joined above 
to the frontal bone; behind to the os planum; before and below 
to the maxillary bone. It sometimes is extended into the nose, as 
low as the upper edge of the inferior spongy bone. 

Ossa Malarum. 

The ossa malarum are the prominent square bones which form 
the cheek, on each side. Before, their surface is convex and 
smooth; backward, it is unequal and concave, for lodging part 
of the temporal muscles. 

The four angles of each of these bones have been reckoned 
as processes. The one at the external canthus of the orbit call- 
ed the superior orbitar process, is the longest and thickest. The 
second terminates near the middle of the lower edge of the orbit 
in a sharp point, and is named the inferior orbitar process. The 
third, placed near the lower part of the cheek, and thence called 
maxillary, is the shortest and nearest to a right angle. The 
fourth, which is called zygomatic, because it is extended back- 
wards to the zygoma of the temporal bone, ends in a point, and, 
has one side straight and the other sloping. Between the two 
orbitar angles there is a concave arch, which makes about a 
third of the external circumference of the orbit, from which a 
fifth process is extended backwards within the orbit, to form near 
one-sixth of that cavity; and hence it may be called the internal 
orbitar process. From the lower edge of each of the ossa ma- 
larum, which is between the maxillary and zygomatic processes, 
the masseter muscle takes its origin. 

On the external surface of each cheek bone, one or more small 



32 OSSA MA LA RUM. 

holes are commonly found for the transmission of small nerves or 
blood-vessels from, and sometimes, into the orbit. On the in- 
ternal surface are the holes for the passage of the nutritious 
vessels of these bones. A notch, on the outside of the internal 
orbitar process of each of these bones, assists to form the great 
slit common to this bone, and to the sphenoid, maxillary, and 
palate bones. 

The substance of these bones is, in proportion to their bulk, 
thick, hard, and solid, with some cancelli. 

Each of the ossa malarum is joined, by its superior and inter- 
nal orbitar processes, to the os frontis, and the orbitar process of 
the sphenoid bone; by the edge between the internal and inferior 
orbitar processes, to the maxillary bone; by the side between the 
maxillary and inferior orbitar process, again to the maxillary 
bone ; and by the zygomatic process to the os temporis. 

Ossa Palati. 

The ossa palati form the back part of the roof of the mouth, 
and extend from it along the external sides of the posterior 
openings of the nose, into the orbits of the eyes. Each bone may 
therefore be divided into four parts, the palate square bone, or 
palatine process, the pterygoid process, the nasal lamella, and 
orbitar process. 

The square bone is irregularly concave, for enlarging both the 
mouth and cavity of the nose. The upper part of its internal 
edge rises in a spine, after the same manner as the palate plate 
of the maxillary bone does, to be joined with the vomer. Its 
anterior edge is unequally ragged, for its firmer connexion with 
the palate process of the os maxillare. The internal edge is 
thicker than the rest, and of an equal surface, for its conjunction 
with its fellow of the other side. Behind, this bone is somewhat 
in form of a crescent, and thick, for the firm connexion of the 
velum pendulum palati ; the internal point being extended back- 
wards, to afford origin to the palato-staphylinus or azygos mus- 
cle. This square bone is well distinguished from the ptervgoid 
process by a perpendicular fossa, which, applied to such another 
in the maxillary bone, forms a passage (pterygo-maxillary) for 
the palatine branch of the fifth nair nf nprvp? • nnH tw nnr>thpr 



OSS A PALATI. 



83 



small hole behind this, through which a twig of the same nerve 
passes. 

The pterygoid process is somewhat triangular, having a broad 
base, and ending smaller above. The back part of this process 
has three fossae formed in it; the two lateral receive the ends of 
the two pterygoid plates of the sphenoid bone; the middle fossa, 
which is very superficial, makes up a part of what is commonly 
called the fossa pterygoidea. The foreside of this pterygoid pro- 
cess is rough and irregular where it joins the back part of the 
great tuberosity of the maxillary bone. Frequently several small 
holes may be observed in this triangular process, particularly one 
near the middle of its base, which a little above communicates 
with the common and proper holes of this bone already men- 
tioned. 

The nasal lamella of this bone is extremely thin and brittle, and 
rises upwards from the upper side of the external edge of the 
square bone, and from the narrow extremity of the pterygoid 
process; it is so weak, and, at the same time, so firmly fixed to 
the maxillary bone, as to be very liable to be broken in separating 
the bones. From the part where the plate rises, it runs up broad 
on the inside of the tuberosity of the maxillary bone, to form a 
considerable share of the sides of the maxillary sinus, and to 
close up the space between the sphenoid and the great bulge of 
the maxillary bone, where there would otherwise be a large slit 
opening into the nostrils. On the middle of the internal side of 
this thin plate, there is a transverse ridge, continued from one 
which is similar to it in the maxillary bone for supporting the 
back part of the os spongiosum inferius. Along the outside of 
this plate, the perpendicular fossa made by the palate nerve is 
observable. 

At the upper and posterior edge of this nasal plate is a notch, 
which when applied to the sphenoid bone, forms the sphenopa- 
latine foramen, through which a nerve, artery, and vein pass to 
the nostril ; this notch forms two processes on the posterior part of 
the bone, the inferior of which is in contact with the internal 
plate of the pterygoid process of the sphenoidal bone, and has, 
therefore, been called by some French anatomists, the pterygoid 



84 OSSA SPONGIOSA INFERIORA. 

apophysis of the os palati. The superior and anterior portion is 
the proper orbitar process of this bone, which is situated at the 
posterior part of the lower surface of the orbit, and forms a por- 
tion of it. This process of the os palati is hollow ; and its cavity 
generally communicates with the contiguous cell of the os eth- 
moides. It has several surfaces, one of which is to be found in 
the orbit, and another in the zygomatic fossa. 

The palate square part of the palate bone, and its pterygoid 
process, are firm and strong, with some cancelli ; but the nasal 
plate, and orbitar processes, are very thin and brittle. 

The palate bones are joined to the maxillary, by the fore edges 
of the palate square bones ; by their thin nasal plates, and part 
of their orbitary processes, to the same bones ; by their ptery- 
goid processes, and back part of the nasal plates, to the pterygoid 
processes of the os sphenoides; by the transverse ridges of their 
nasal lamellae to the ossa turbinata inferiora, and by the spines of 
the square bones to the vomer. 

The Ossa Spongiosa, or Turbinata Inferiora. 

The ossa spongiosa, or turbinata inferiora, are so named to 
distinguish them from the upper spongy bones, which belong to 
the os ethmoides ; but these lower spongy bones are quite distinct, 
and connected in a very slight way with the upper jaw bones. 
They are rolled or convoluted, very spongy, and exceedingly 
light. Each of them is attached to the os maxillare superius, 
near the transverse ridge, by a hook-like process, and covers a 
part of the opening of the maxillary sinus. One end is turned 
towards the anterior opening of the nose, and covers the end of 
the lachrymal duct ; the other end of the same bone points back- 
wards towards the throat. The curling plate hangs down into 
the cavity of the nostril, with its convex side towards the septum. 
This spongy bone differs from the spongy processes of the eth- 
moid bone, in being less turbinated or complex, and in having no 
cells connected with it. 

The Vomer. 
The vomer is a thin flat bone, which forms the back part of the 



THE VOMER. 



85 



septum of the nose. Its posterior edge extends downwards from 
the body of the os sphenoides to the palatine processes of the 
ossa palati, separating the posterior nares from each other. 

The figure of this bone is an irregular rhomboid. Its sides are 
smooth ; and its posterior edge appears in an oblique direction 
at the back part of the nostrils. The upper edge is firmly united 
to the base of the sphenoid bone, and to the nasal plate of the 
ethmoid. It is hollow for receiving the processus azygos of the 
sphenoid, and where it is articulated to the nasal plate of the 
ethmoid, it is composed of two lamina which receive this plate 
between them. The anterior edge has a long furrow in it, where 
the middle cartilage of the nose enters. The lower edge is 
firmly united to the nasal spines of the maxillary and palate bone. 
These edges of the bone are much thicker than its middle, which is 
as thin as paper ; in consequence of which, and of the firm union 
or connexion this bone has above and below, it can very seldom 
be separated entire in adults ; but in a child it is much more 
easily separated entire, and its structure is more distinctly seen. 

Its situation is not always perpendicular, but often inclined and 
bent to one side, as well as the nasal plate of the ethmoid bone. 

It is united above to the os sphenoides and the nasal plate of 
the ethmoid bone ; before to the middle cartilage of the nose ; 
and below, to the ossa palati and ossa maxillaria superiora. 

Maxilla Inferior, or Lower Jaw. 

The form and situation of this bone are so generally known, 
that they do not require description. To acquire an accurate 
idea of the lower jaw, it is, however, necessary to examine at- 
tentively its different parts : viz. the chin, the sides, the angles, 
and the processes. 

In the subjects where the bones are strongly marked, there is 
a prominent vertical ridge in the middle and most interior part 
of the chin which becomes broad below so as to form a triangle, 
and on each side of this triangular prominence are transverse 
ridges; from these eminences the muscles of the lower lip 
originate. 

On each side of the jaw, commonly under the second of the 

VOL. I. 8 



86 MAXILLA INFERIOR. 

bicuspides,or small molar teeth, is the anterior maxillary foramen, 
through which pass out the remains of the inferior maxillary nerve 
and blood-vessels. This foramen, has a direction upward and 
backward. At a small distance behind these foramina, on each 
side is the commencement of a ridge which continues backward 
until it forms the edge of the anterior or coronoid process. The 
alveolar processes, which form the upper edge of the jaw, are on 
the inside of this ridge ; the alveoli or sockets corresponding 
with the roots of the teeth, in number and form. The lower edge 
of the jaw, which is denominated the base, is round and firm, ex- 
cept at the angles, where it is thin. 

The angle is formed at the posterior extremity of the base: in 
children it is obtuse; but in adults whose teeth are perfect, it is 
nearly rectangular. The masseter muscle is inserted into the 
lower jaw, at the angle ; and there are several inequalities on 
the surface made by this muscle. 

The anterior or coronoid process, is rather higher than the pos- 
terior, and forms an obtuse point : into this process the temporal 
muscle is inserted. The anterior edge of the coronoid process 
is sharp, and continued into the ridge above mentioned ; from 
this edge the buccinator muscle arises. As the alveoli are on 
the inside of this edge and ridge, the jaw is very thick at this 
place. There is a semicircular notch between this process 
and the posterior or condyloid; and here the bone is very thin. 
The condyles are oblong, and are placed obliquely; so that 
their longest axes, if extended until they intersect each other, 
would form an angle of more than one hundred and forty de- 
grees. The neck of the process, or the part immediately below 
the condyle, is concave on the anterior, and convex on the pos- 
terior surface. 

On the inside of the jaw, in the middle of the chin, is a small 
protuberance, sometimes divided by a vertical fissure ; to this 
are attached the fraenum linguas, and some muscles of the tongue 
and os hyoides. Farther back is a ridge which extends 
backwards and upwards, until it approaches the alveoli of the 
last molar teeth ; where it terminates in an oblong protuberance. 
To the anterior part of this line the mylo-hyoidei muscles are 



MAXILLA INFERIOR. 



87 



attached; and to the posterior extremity, the superior constrictor 
of the pharynx. The surface of the bone above this ridge is 
smooth, and covered with the gums and lining membrane of the 
mouth. The surface below the posterior part of the line is rather 
concave, to accommodate the submaxillary gland. 

At a small distance behind the alveoli, and nearly on a line 
with them, midway between the roots of the two processes, is a 
large foramen for transmitting the third, or inferior maxillary 
branch of the fifth pair of nerves, and the blood-vessels which 
accompany it ; the canal, which commences here, terminates at 
the anterior foramen, already described. The surface of this 
canal is perforated by many foramina, through which blood- 
vessels and nerves pass to the different teeth, and to the cancelli 
of the bone. On the anterior side of the foramen is a sharp- 
pointed process, from which a ligament passes to the temporal 
bone. The nerve and vessels, before they enter into this fora- 
men, make an impression on the bone; and there is generally a 
small superficial groove which proceeds downwards from it, 
being made by a small nerve which supplies some of the parts 
under the tongue. 

At the angle of the jaw, on the inside, is a remarkable rough- 
ness, where the internal pterygoid muscle is inserted. 

The lower jaw moves like a hinge upon its condyles in the 
glenoid cavity, when the mouth opens and shuts in the ordinary 
way. When the mouth is opened very wide, the condyles move 
forward upon the tubercles before the cavities : if the effort to 
open the mouth is continued, the lower jaw is fixed in that situa- 
tion, and the whole head is thrown back, which separates the 
upper jaw still farther from the lower. 

The lower jaw can be projected forward without opening the 
mouth, by the movement of both condyles, at the same time, on 
the tubercles. 

This bone can also rotate upon one condyle, as a centre, while 
the other moves out of the glenoid cavity, upon the tubercle: but 
these important motions can be better understood, after the mus- 
cles, and the articulation with the temporal bone, in its recent 
state, have been described. 



qq OF THE TEETH. 

Of the Teeth. 

In the adult, when the teeth are perfect, there are sixteen in 
each jaw, and those in corresponding situations, on the opposite 
sides, resemble each other exactly. 

They are of four kinds, viz. incisores, or the fore teeth ; cus- 
pidati, or the canine ; bicuspides, or the small grinders ; and mo- 
lares, or the large grinders. 

On each side of the jaw, supposing it divided in the middle, 
there are tivo incisores, one cuspidatus, two bicuspides, and three 
molares. They occur in the order in which they have been 
named, beginning at the middle of the jaw, as in the following 
figure. 



Fig. 8. 






Each tooth is divided into two parts, viz. the body, or that por- 
tion which is bare, and projects beyond the alveoli and gums; 
and the root, which is lodged in the socket. The boundary be- 
tween these parts, which is embraced by the gums, is called the 
neck of the tooth. 

The body and roots consist of bone, which is more firm and 
hard than the substance of the other bones ; but all the surface 
of the body, which projects beyond the gums, is covered with 
enamel, a substance very different from common bone. 

Every tooth in its natural condition has a cavity in it, which 
commences at the extremity of each root, and extends from it to 



COMPOSITION OF THE TEETH. g9 

the body of the tooth, where it enlarges considerably. This 
cavity is lined by a membrane, and contains a nerve, with an 
artery and vein, which originally entered the tooth, by a fora- 
men near the point of the root, as is evident during the growth 
of the teeth. These vessels, and the nerve, have been traced 
into the teeth ; although in many subjects the foramina appear 
to be closed up. 

Composition of the Teeth. 

— The bone or ivory of the teeth, (see Fig. 9.) constitutes the 
whole of the root, and a greater part of the body and neck. 
The cavity in the centre, for the lodge- 
ment of the pulp, in whichever of the Fig- 9 - 
teeth it is examined, presents an exact 
similarity of shape to the bodies and 
fangs of the teeth, as though the latter 
had been moulded upon the pulp. 
— The ivory is of a polished pearly 
whiteness, like that of a piece of white 
satin. It is composed chemically both 
of animal and earthy matter, but in 
different proportions from ordinary bone. If exposed for a 
considerable time to the action of a weak acid solution, the 
earthy matter is dissolved, and there is left a flexible, tenacious, 
dense, and homogeneous mass, much resembling cartilage, but 
more dense. If, on the contrary, it is exposed to the action of 
fire, the animal matter is first blackened, then consumed, and 
there is left a white, hard, friable residue of calcareous matter. 
— The enamel or vitreous substance, (see Fig. 9,) so named from 
its resemblance to vitrified minerals, has been with greater pro- 
priety called by Blake, the cortex striatum, from the lines which 
it presents upon its sides. It forms a covering nearly a line in 
thickness upon the crown of the teeth, and is thinned down at its 
termination upon the neck. Its texture is fibrous or consists of 
particles piled one upon another, perpendicularly to the bony 
part, and so closely compressed together, as to leave no obvious 

8* 





90 COMPOSITION OF THE TEETH 

interval between them. All the wear of the teeth takes place, 
therefore, at the end of these fibres and not upon their sides ; 
and the enamel is rendered by this arrangement much less liable 
to fracture. 

— No vessels have been traced to this substance, nor has it 
ever been seen like the bony portion, coloured by madder in 
young animals fed on this substance during the developement 
of the teeth. But Mascagni, infatuated with his discoveries in 
the absorbent system, absurdly regarded this substance as en- 
tirely formed of absorbent vessels.* It is exceedingly hard and 
strikes fire, on collision with steel. While covering the bone, it 
presents a milky white appearance ; removed from it, it is semi- 
transparent and opaline. 

— The enamel is thickest on those parts of the teeth most ex- 
posed to friction, as on the horizontal surfaces of the grinders, 
the edges of the incisors, and the points of the cuspidati. The 
position of the enamel and its arrangement into fibres is well seen 
in Fig. 9. 

— The enamel and ivory of the teeth are the most indestructible 
after death of all parts of the body. In opening tumuli or other 
ancient places of sepulchre, they are frequently found to have 
undergone scarcely any decomposition. 

— The chemical composition of the two substances of the human 
teeth, consists, according to Berzelius, in the hundred parts, of 

Enamel. Bone. 

Animal matter, .... . 20.0 

Phosphate of lime, with fluate of lime, 88.5 - 64.3 

Carbonate of lime, ... 8.0 - 5.3 

Phosphate of magnesia, - - 1.5 - 1.0 

Soda, with some chloride of soda, - - 1.4 

Free alkali and animal matter, - 2.0 



100.0 100.0 



* Vide Prodrome-. 



PURKINJE AND MULLER ON THE TEETH. 



91 



— Purkinje and Miiller, have recently, with the aid of the micro- 
scope, investigated very minutely, the structure of the teeth. 
They describe the bony part of the tooth as consisting of fibres 
running parallel to each other from the external to the internal 
surface of the tooth, between which is placed a semi-transparent, 
homogeneous portion. These fibres they believe to be really tu- 
bular; for on bringing ink into contact with them, it was drawn 
into them, as if by capillary attraction. These tubes Miiller 
believed to be filled, at least partially, with calcareous matter, 
which was the cause of the whiteness and opacity of the tooth. 
In the more transparent parts of carious teeth, the white sub- 
stance in these tubes presented more of a granular, and less of 
a compact appearance, under the microscope, than in a sound 
tooth. 

— The white colour and opacity of these tubes were removed 
by the application of acids. On breaking a thin lamella of a 
tooth transversely in regard to the fibres, and examining the 
edge of the fracture, he perceived the tubes, stiff, straight, and 
inflexible, projecting here and there from the surfaces. If the 
lamella had previously been acted on by acid, the tubes were 
flexible, transparent and often very long. Hence Miiller in- 
ferred that the tubes have a basis of animal tissue, and that 
besides containing calcareous matter in their cavity, they have 
this tissue in the natural state impregnated with calcareous salts. 
The greater part of the earthy matter of the tooth is, however, 
contained in the transparent homogeneous portion between the 
fibres, in which it can be rendered visible in a granular state by 
boiling thin lamina of teeth in a ley of potash. 
— Purkinje, by the aid of the microscope, discovered the cor- 
puscles that characterise true bone, in layers taken from the 
external and internal surface of the root ; he considers the great 
mass of the tooth, however, as destitute of organisation. — 

The alveoli or sockets of the teeth, are formed upon the edge 
of the jaw : the bone, of which they consist, is less firm than any 
other part of the jaws : they correspond exactly with the roots 
of the teeth; and are lined with a vascular membrane which 



92 OF THE ALVEOLI. 

serves as a periosteum to the roots, and assists in fixing them 
firmly. 

— They are developed pari passu, with the teeth, and solely for 
the purpose of giving them a lodgement; hence when the teeth 
are removed from the jaw, in the living subject, the sockets sub- 
sequently disappear by absorption, as being of no further use. 
There are two sets of alveoli, one for the deciduous teeth of the 
child, and one for the permanent teeth of the adult. Their walls 
are formed of one plate on the external side of the jaw, and one 
on the internal, with transverse bony laminae passing between 
them. On the side of the cavity which they form, their substance 
is loose and cellular ; on their outer side like other bones, they 
are smooth and compact. 

— The transverse processes, are rather more prominent than the 
lateral part of the parietes, corresponding in this respect inversely 
with the line of enamel on the teeth. 

— The enamel terminates on the neck of the teeth a little above 
the level of the sockets, leaving a small space on the bony part 
of the neck round which the gum is attached. 
— The alveoli, terminate in as many hollow processes, as there 
are fangs to the teeth which they lodge : and at the bottom 
of each of these processes there are one or more minute fora- 
mina, for the transmission of vessels and nerves to the internal 
membrane and pulp of the teeth. 

— The mode of articulation of the teeth in the sockets is called 
gomphosis; even in their perfect state, the teeth are slightly 
movable in the socket, of which dental surgeons, occasionally 
take advantage, in altering the direction of the teeth, by me- 
chanical means. The firmness of the articulation, depends upon 
the adaptation in size and shape of the sockets to the fangs, on the 
gum which surrounds the neck, of the periosteum of the sockets 
which is continuous with that of the fangs, and of the vessels and 
nerves, which enter into the foramina, of the fangs. 

The teeth of different kinds differ greatly from each other, in 
form and size. 

The body of the incisores is broad, with two flat surfaces, one 
anterior and the other posterior; the anterior surface is rather 



OF THE TEETH. 



93 



convex, and the posterior concave ; they meet in a sharp cutting 
edge. At this edge the tooth is thinnest and broadest ; it gradu- 
ally becomes thicker and narrower, as it is nearer the neck. The 
enamel continues farther down, on the anterior and posterior sur- 
faces than on the sides. 

The incisores of the upper jaw are broader than those of the 
lower; especially the two internal incisores. 

The cuspidati are longer than any other teeth, and are thicker 
than the incisores. Their edges are not broad, as those of the 
incisores, but pointed ; this point is much worn away in the pro- 
gress of life. 

The enamel covers more of the lateral part of these teeth than 
of the incisores. 

The bicuspides are next to the cuspidati, two on each side. 
They resemble each other strongly ; but the first is smaller than 
the other, although it generally has a longer root. The bodies 
are flattened laterally, but incline to a roundish form. On the 
middle of the grinding surface are depressions which make the 
edges prominent. On the external edge there is generally one 
distinct point in each of the bicuspides. The internal edge is 
lower than the external in the first bicuspis, which gives it a re- 
semblance to the cuspidatus. In the second bicuspis, the internal 
edge is more elevated, although the point is not so distinct as it is 
on the external edge. 

The bicuspides have generally but one root, which is often in- 
dented lengthwise, so as to resemble two roots united. 

The three molares or large grinders, are placed behind the bi- 
cuspides, on each side. The first and second strongly resemble 
each other, but the third has several peculiarities. The body of 
the large grinders is rather square ; the grinding surface has often 
five points, and three of these are on the external side. In the 
upper jaw these teeth have three roots, two situated externally, 
and one internally, which is very oblique in its direction ; they 
are all conical in their form. It seems probable that the roots of 
these teeth are arranged in this way to avoid the antrum maxil- 
lare. The molares of the lower jaw have but two roots, which 
are flat, and are placed one anterior and the other posterior; in 



94 OF THE TEETH. 

each of these broad roots there are two canals, leading to the 
central cavity; whereas, in each root of the upper molares there 
is but one. The third grinder is called dens sapientice, from its 
late appearance. It is shorter and smaller than the others; its 
body is rather rounder, and its roots are not so regular and dis- 
tinct; for they are sometimes compressed together, and some- 
times there appears to have been but one root originally, when the 
whole tooth has a conical appearance. In some cases the dentes 
sapientise take an irregular direction, and shoot against the ad- 
joining teeth. 

Infants have a set of deciduous teeth, which differ in several 
respects from those of adults. They are but twenty in number; 
the five on each side of each jaw, consist of two incisores, one 
cuspidatus, and two molares or large grinders. The first of them 
generally protrudes through the gums between the fourth and 
eighth months of age; the last about the end of the second year. 
They commonly appear in pairs,* which succeed each other at 
irregular intervals. Those of the lower jaw are, in most cases, 
the first. The order of their appearance is this : the central in- 
cisores appear first, then the external incisores on each side; after 
these the first molaris, then the cuspidatus, and finally the last 
molaris on each side. There are many deviations from this or- 
der of succession, but it takes place in a majority of cases. 

These deciduous teeth become loose, and are succeeded by 
those which are more permanent, nearly in the same order in 
which they appeared, but with a progress much more slow. 
The incisores generally become loose between the sixth and 
seventh year; the first molares about the ninth, the cuspidati 
and the second molares not until the tenth or twelfth, or even 
fourteenth year. The bicuspides take the places of the infant 
molares. 

The three permanent molares appear in the following order: the 
first of them protrudes a short time before the front teeth are shed ; 
it is the first of the permanent teeth which appears, and is seen 
between the sixth and seventh year. The second molaris appears 
soon after the cuspidati and the second bicuspides are seen. 

* The two teeth of a pair do not appear at the same precise time, but very near 
to each other. 



DEVELOPEMENT OF THE TEETH. qk 

There is then a long interval ; for the last molaris or dens sapi- 
entiso is seldom seen before the twentieth year, and sometimes not 
until the twenty-fifth. 

The teeth are formed upon pulpy substances, which are situ- 
ated in the alveoli, and are contained in capsules. A shell of bone 
is first formed upon the surface of the pulp, which gradually in- 
creases, and the pulp diminishes within it. The body of the tooth 
is produced first, and the root is formed gradually afterwards; 
during its formation the root has a large opening at the extremity, 
which is gradually diminished to the small orifice before de- 
scribed. The roots, as well as the body, are formed upon the 
pulpy substance, which gradually diminishes, as they increase. 
After the external surface of the body of the tooth is formed, the 
enamel begins to appear upon it, and gradually increases, until it 
is completely invested. It is probable that the enamel is deposit- 
ed upon the body of the tooth by the membranous capsule which 
contains it. This substance, which appears to be formed of ra- 
diated fibres, is harder and less destructible than bone. Like the 
substance of bone, it is composed of phosphate, with a small pro- 
portion of the carbonate of lime ; but it is destitute of the car- 
tilaginous or membranous structure which is demonstrable in 
bone. 

The pulpy substances, or rudiments of teeth, may be seen in 
the fetus, when about four months old. At six months, ossifica- 
tion can be seen to have commenced on the pulps of the incisores. 
At the time of birth, the bodies of the infant teeth are distinctly 
formed. The alveoli, at first, have the appearance of grooves in 
the jaw, which afterwards are divided by transverse partitions ; 
they enlarge, in conformity to the growth of the teeth, and appear 
to be altogether influenced by them. 

The permanent teeth are formed very early : the rudiments of 
the first permanent grinder on each side have commenced their 
ossification at birth. At the same time, the rudiments of the per- 
manent incisores are to be perceived; and their bodies will be 
found nearly ossified, by the time the infant incisores are pro- 
truded completely through the gums. About the age of six years, 
if none of the infant teeth are shed, there will be forty-eight teeth 



gg DEVELOPEMENT OF THE TEETH. 

in the two jaws, viz. the twenty infant, and twenty-eight perma- 
nent teeth, more or less completely formed. 

—From their mode of developement, structure, and con- 
nexions with the rest of the economy, the teeth have been consi- 
dered analogous to the hair, nails, and feathers, of mammiferae 
and birds, and to the shells of molluscse. It cannot be said that 
the teeth are absolutely inorganized, that they are mere concre- 
tions of an effused fluid, since there is no part appertaining to 
living beings, entirely destitute of life ; but in the hard structure 
of the teeth, no anatomist has yet demonstrated either vessels 
or nerves, though there are practical dentists, who assert that 
they have seen blood issue from the bony part of the teeth, in 
some of their operations.* 

* Hunter denies positively the existence of any vessels passing between the pulp 
and bone of the teeth, as he was not able to render them manifest by injection, as 
the colouring matter does not pass into them when animals are fed upon madder, 
except in the forming state, and as they do not share in the general softening of 
the bones, in rickets and malacosteum. Blake believed that these vessels did exist, 
but were difficult to demonstrate, like those that we know to pass in the eye from 
the capsule of the crystalline lens, to the lens itself; Beclard, that there were no 
vessels in the bone of the teeth, continuous with those of the pulp, but that the 
former received continually from the latter a nourishing liquid which penetrated 
it by imbibition, and that it was situated in regard to the pulp, as the hair and 
nails to the vascular part of the skin. But the morbid alterations which take 
place in the body of the teeth, the softening and exostosis seen frequently at the 
roots of the teeth, and the fusion of the latter occasionally to the bottom of the 
alveoli, render their vascularity highly probable. 

The fang of a perfectly developed tooth, is covered closely by a membrane, 
called its periosteum, which is continuous with the periosteum of the socket, and 
is on all hands admitted to be vascular; the internal cavity is also lined by a 
highly nervous and vascular membrane. Both of these are intimately connected 
with the bony structure of the tooth, and require a little force to separate them. 
This connexion Bell believes to be made by vessels and probably nerves, which 
pass between them and the bone. 

Though no artificial injection has been made of the teeth, this writer has seen 
them tinged with a bright yellow in a young woman who died of jaundice; and 
when death has taken place from hanging or drowning, when there is usually 
a congestion of the capillary system, " he has found the osseous part colour- 
ed with a dull deep red which could not possibly take place if they were de- 
void of a vascular system ; in both instances the enamel remained wholly free from 
discoloration." I have observed the same thing in the teeth of subjects who have 
died of cholera. The existence of nerves in the bony part of the teeth Bell consi- 



DEVELOPEMENT OF THE TEETH. 



97 



— The teelh are formed of concentric layers, and if the pulp 
which produces them be destroyed from any cause, they lose the 
little vitality that they may possess, become foreign bodies me- 
chanically retained in the living parts, and sooner or later are 
thrown off. 

— The teeth are distinguished from the bony tissue, by the ab- 
sence of any demonstrable cellular or vascular parenchyma in 
their composition, by their being in part exposed to the contact 
of the atmosphere, which no bone can be without losing its 
vitality, by the enamel which covers them externally, by their 
successive evolution and renovation at certain periods of life, 
and lastly by their wearing out, and being lost in old age, whilst 
the vital actions are still going on in the rest of the economy. 
— In many of the lower animals the teeth are evidently a pro- 
duction of the skin or dermoid tissue, which is reflected in at the 
commencement of the digestive passages, and many modern 
anatomists have for the reasons above mentioned, connect- 
ed them with the description of the digestive organs; other 
anatomists of distinction, have, however, for purposes of con- 
venience to the student, chosen to describe them with the bones 
in which they are developed. 

Developement of the Teeth. 

— The teeth, as we have before observed, are developed on a 
principle different from that of other parts of the body, by 
germes or gemmules. If the jaws of a foetus are examined with 
care, even at the period of two months* after conception, an 

ders manifested by the facts commonly observed by dentists ; in filing the teeth 
no pain whatever is produced till the enamel is removed ; but the instant the file 
begins to act upon the bone, the sensation is exceedingly acute : and when the 
gums, alveoli and periosteal lining membrane, have receded from the teeth so as to 
leave the bony part bare, it is exquisitely sensitive when touched with any hard 
instrument. 

He admits likewise the existence of absorbents in the bony part of the teeth, 
for in a tooth in which inflammation had existed for a considerable time, he found 
after its extraction an abscess in the very centre of the bony structure, communi- 
cating with the natural cavity and filled with pus. — p. 

* T. Bell — Beclard. 

VOL. I. 9 



98 DEVELOPEMENT OF THE TEETH. 

extreme]}' soft, jelly-like substance is seen lying along the edge 
of each maxillary arch. At the third month it is more consist- 
ent, and two plates of bone have sprung up at its sides, which 
are the rudiments of the external and internal alveolar plates. 
Shortly after this period, the pulpy substance separates into dis- 
tinct portions, and rudiments of the transverse plates of the al- 
veoli are seen shooting across, from side to side. These distinct 
portions of the pulpy substance, are the germs or rudiments 
from which the teeth are formed ; each is partially enclosed in a 
sac, and receive branches from the vessels and nerves which run 
along the bottom of the groove. At the fourth month, the enve- 
loping sac is thick in its texture, and consists of two layers, 
which are easily separated after a short maceration. Both of 
these layers, Fox and T. Bell have proved, by their injections, to 
be vascular :* laying loosely within this double sac is the gela- 
tinous vascular pulp itself, covered by an extremely thin, delicate 
vascular membrane, (to which it is closely united by vessels,) 
which secretes the bony part of the tooth, and is a sort of inter- 
nal periosteum.f The pulp and its membrane receive their vas- 
cular and nervous filaments from the proper dental vessels and 
nerves, which run along the groove in the jaw. The double sac- 
cular membrane receives its vessels and nerves solely from the 
gums; and the only attachment between this and the membrane 
of the pulp, is near the base of the latter, where the dental vessels 
enter it. The sac is closely united to the gum, hence if we tear 
the gum that covers the jaws, we necessarily bring with it the 
entire structure of the germ. 

— If at this period, the fourth month, we open the germ, we find 
the pulp presenting exactly the size and shape of the body of the 
teeth first cut, (incisors) and that its membrane has already com- 
menced the deposit of its bony tip. 
— At birth, ossification will be found to have commenced on all 

* Hunter declared, that the external is soft and spongy, without any vessels ; 
the other is much firmer, "and extremely vascular." Blake on the contrary as- 
serts, that the external is spongy and full of vessels, the internal one is more ten- 
der and delicate, and seems to contain no vessels capable of containing red blood. 

t This membrane is called by Bell the proper membrane of the pulp, and was 
conjectured by Blake, with much probability, to be a " propagation of the perios- 
teum of the jaw." Blake on the Tc ;«! 



OF THE ENAMEL. 



99 



the pulps of the temporary teeth, (the body of the incisors being 
nearly completed,) and on each of those of the anterior perma- 
nent grinders. The commencement of ossification is by three 
points in the incisors, which form their serrated edges, as seen 
on their first developement, by a single point for the canine, two 
for the bicuspide, and three, four, or five on the large molar, ac- 
cording to the number of processes which they present. Continu- 
ous deposition of the bony matter from the membrane of the 
pulp, unites these points together, and by degrees at different 
epochs, all the bodies are formed; the pulp retiring as it were, 
as the deposition of bone goes on and encroaches upon its cavity, 
and elongates itself downward, into the shape of the fang. This 
is finally formed in the same manner as the bodies, and the pulp 
is completely enclosed in the bony case of the tooth, except at 
the foramina where the vessels and nerves enter. Where more 
than one fang exists to a tooth, the lower part of the pulp, is pre- 
viously divided into an equal number of processes, by little bony 
partitions which shoot across from the sides of the alveoli. 

Of the Enamel. 
— When the developement of the bony shell has proceeded as 
far as the completion of the body and neck, the internal layer 
becomes thickened and more vascular, receives a greater amount 
of blood, becomes closely attached to the neck, and forms a 
loose capsule over the body. From the internal face of this 
membrane, is poured out a thickened whitish fluid, which Ber- 
zelius considers of the nature of lactic acid, which is speedily 
consolidated into a dark chalky substance, deposited first upon 
the tips of bone, and gradually extending down in layers till it 
covers the whole crown of the teeth. This is the enamel. It 
becomes gradually whiter and harder, as though by a more per- 
fect crystallization, but (near to the period at which the teeth are 
cut,) it is still so soft, as to be frequently cut with the gum lancet.* 

* In man, the enamel is formed solely by the inner membrane of the sac. The 
external contributes nothing to the structure of the teeth. But in graminivorous 
animals, where the flinty covering of the food they feed on requires a more per- 
fect grinding apparatus, it performs an important part, in adding another element 
to the structure of the molar teeth, called by Blake crusta petrosa. The cutting 
teetli are constructed as those of man. In these animals the enamel of the grind- 



100 DEVELOPEMENT OF THE TEETH. 

—Of the three membranes of the germ or follicle, one only may 
be considered as permanent, that of the pulp or internal, which 
secretes the bone of the tooth. 

— The two outer, or those of the sac, cover the crown of the 
tooth ; and as this is pushed forwards by successive depositions 
of bony matter from within, they are pressed upon and wasted 
away by absorption, like the gum, in direct proportion with the 
advancement of the tooth, so that in perfectly natural dentition, 
there is little tension or pressure felt. This is called cutting the 
teeth, a name which expresses the fact, sufficiently well, but 
literally conveys a wrong idea. 

— In cases of difficult dentition, the membranes of the sac re- 
tain their density and vascularity, and are probably thickened 
by inflammation, and the bony layers formed from the pulp, 
resisted in their advancement by these membranes, make com- 
pression upon the pulp and dental nerves; this, like continued 
pressure made in other parts of the body, becomes exqui- 
sitely painful, and gives rise to distressing sympathetic disturb- 
ances. The relief procured is by cutting the gums and sac, 
which will be more or less immediate, according to the degree 
of compression and inflammation of the pulp. 
— The periosteum covering the fangs of the tooth, is a reflected 
continuation of the periosteum lining the socket, and this again 
is continuous with that lining the jaw. 

Of the Permanent Teeth. 

— The adult or permanent teeth, are developed in a manner 
almost exactly analogous to the deciduous or infantile. The 

ers does not form a continuous smooth layer as in man, but passes a little way 
into the body of the teeth, and is arranged in the form of vertical layers, between 
which after the inner membrane of the sac has been removed by absorption, the 
outer one, according to Bell, deposits the pars petrosa, and fills up the intervening 
space. This is a substance harder than the bone, but softer than the enamel; and 
the advantage derived from it is, that it is worn off by trituration more readily 
than the enamel, so that the latter is constantly maintained in sharp prominent 
lines upon the surface of the teeth. The same object is here insensibly attained, 
as a natural consequence of the difference in density of these parts, which the 
miller effects with much labour with his pick-hammer, on the burr-stones of his 
mill — p. 



DEVELOPEMENT OF THE TEETH 



101 




germs of many of them are distinctly perceptible in the gums 
of the infant at birth. They are placed at first deep in the jaw 
at the inner side of those of the deciduous teeth, to the sac of 
which they are attached at top by a neck-like process, as seen 
in Fig. 10. As the infantile teeth rise up and make their way 
through the gum, this 
process becomes con- 
nected with the gum, 
and forms what is 
called by Hunter the 
gubernaculum dentis, 
from its influence in 
giving the permanent 
teeth their proper vertical direction, and preventing their making 
their way at random through the sides, as they do occasionally 
in cases where the gubernaculum has been destroyed. 
— Delabarre has given the gubernaculum the name of iter dentis, 
from an erroneous belief that it was tubular, like the duct of a 
sebaceous follicle, and gradually opened as the tooth progressed. 
— At the fifth month of foetal life, according to Bell, and the 
eighth and ninth, according to Blake and Fox, the germs of the 
first permanent molars, may be seen at the outside of the infantile 
row, and those of the permanent incisors behind the deciduous. 
Fig. 10 — 1, 2, shows the attachment of the incisor and molar 
germs of the two sets, just prior to the eruption of the first. The 
permanent germ is at first placed in the socket of the deciduous 
tooth, of which it appears, on first view, to be an offshoot or 
gemmiperous production. Its vessels and nerves are believed to be 
mere branches of those of the deciduous 
set. By degrees a distinct socket is 
formed for it behind the latter, and its 
process or gubernaculum is elongated, as 
seen in Fig. 10—3. When the decidu- 
ous teeth have cut the gum, the two 
sockets are completely distinct, as seen 
in Fig. 11, and the gubernaculum is at- 
tached to the gum. 

9* 



Fig. 11. 




102 DEVELOPEMENT OF THE TEETH. 

— Ossification first commences in the permanent set on the an- 
terior molares, and may be seen at birth ; at the age of twelve 
months, it has progressed to a considerable extent upon these as 
well as upon the incisors and the lower cuspidata. At the sixth 
or seventh year of age the whole of the permanent teeth are more 
or less ossified, and the incisors are so far completed as to be 
nearly ready to make their appearance through the gum. At 
this period there are no less than forty-eight teeth in the two 
jaws, the twenty deciduous and the twenty-eight permanent, 
which are in different degrees of developement. The last mo- 
lars do not begin to ossify till the ninth year, and are the last of 
all to make their appearance through the gum, whence they 
have received the name of denies sapientice or wisdom teeth. 
— The permanent teeth, which are more in number and individu- 
ally of larger size and form a larger arch than the temporary, 
are developed at successive intervals, so as to correspond ex- 
actly, with the increasing size of the jaws from the infantile to the 
adult state. Hence they cannot correspond in position with the 
deciduous teeth ; the outer permanent incisor will rise up near the 
cuspidatus, and the permanent cuspidatus near the first molar of 
the deciduous set. 

— Exactly in proportion as the bodies of the permanent teeth are 
completed and approach the gum, the roots of the deciduous are 
removed by absorption, till finally the bodies of the latter only 
are left fixed mechanically in the gum, and are tumbled off at the 
slightest effort. The process of the removal of the fangs is not 
perfectly understood; it is not as was once supposed produced by 
the pressure of the subjacent tooth, for very frequently the com- 
mencement of absorption is at the neck, and not at the root of 
the tooth, where no pressure can come, and occasionally takes 
place even where the germ of the permanent tooth has been de- 
stroyed. It is more probably owing to the enlarged vessels of 
the growing permanent teeth, which come from the same branch 
with those of the deciduous, carrying off all its blood by deri- 
vation, which leads to the wasting of the latter set, a process of 
which we find the analogue in the developement of many parts 
of the feet us. 



DEVELOPEMENT OF THE TEETH. i^o 

— Below is a tabular view of the appearance of the temporary 

teeth, and also of the periods at which they are changed for the 

permanent. 

— It is to be taken, however, as a general rule liable to continual 

exceptions, not only in regard to the time, but also as to the 

regular order of appearance. As a general rule, the teeth of the 

lower jaw appear first, then the coresponding teeth of the upper. 

Deciduous Teeth. 

From 5 to 8 months, the four central incisors, 

" 7 " 10 " four lateral incisors, 

" 12 " 16 " four anterior molares, 

" 14 " 20 " four cuspidati, 

" 18 " 36 " four posterior molares. 

Permanent Teeth. 

— The first permanent molares usually pierce the gum before the 
fall of the central incisors, and their appearance indicates the ap- 
proaching change. 

— The following are about the medium periods at which they 
are cut, but there is a great degree of variation in this respect. 
Those of the lower are here indicated, and they most commonly 
precede the upper by about two or three months. 

About 6^ years, the anterior molares, 

" 7 " central incisors, 

" 8 " lateral incisors, 

" 9 " anterior bicuspides, 

"10 " posterior bicuspides, 

11 to 12 " cuspidati, 

12 " 13 " second molares, 

17 " 19 " third molares or dentes sapientice. 

— Fig. 8 is a side-view of a beautiful set of the permanent teeth 
of both jaws, fitted in their sockets, showing the exact manner 
in which the surfaces of each set are adjusted to each other, and 
the smaller dimensions of the fangs of the wisdom teeth, owing 



104 ABERRATIONS OF DENTITION. 

to the contracted space in which they are developed. These 
teeth decay early, are comparatively of little utility, and probably 
from the same cause ; for in cases, where prior to their develope- 
ment one of the molares in front of them have been removed, 
they take a more forward position, are developed with larger 
fangs, and become much more serviceable. 
— When the first teeth have made their appearance through the 
gum, they are not yet completed ; the process of thickening the 
body by layers from within, and of lengthening the root below, 
is for a time still continued by the pulp. After their completion, 
the only physiological changes they undergo, is the wearing 
down of the bodies by friction, and the filling up of the top of 
their cavity within by the pulp, with a yellowish bony matter in 
old age, which prevents the exposure of the cavity, and protects 
the vasculo-nervous pulp, which is so exquisitely sensitive, as to 
be considered by some in the light of a nervous ganglion. This 
latter process unhappily is not universal, and is especially defec- 
tive when the teeth decay early in life, apparently before the 
period nature has assigned them. 

Aberrations of Dentition. 

— Occasionally at birth teeth have been found developed on the 
surface of the gum, as in the cases of Louis XIV. of France 
and Richard III. of England : in such cases they are generally 
mere shells, and are quickly shed, and below exist the double 
series of germs, which are developed in the regular order. 
— In some rare cases, from the non-existence or disease of the 
germs, no teeth have ever been developed.* Borelli mentions a 
case of this sort occurring in a woman then seventy-two years 
old. 

— Sometimes the temporary teeth only exist, which fall at the 
regular period and are never replaced. Occasionally the set 
of permanent teeth have consisted of double or molar teeth all 
round. Sometimes the appearance of the temporary teeth has 
been protracted to the sixth or seventh year, and even then fol- 
lowed at regular intervals by the permanent set. The number 

* Oudet. Consid. sur la Nature des Dents et leur Alterations; Journal Univ. Des 
Sciences Med. torn. 43, 1826. 



O:? HYOIDES. 



105 



of .the permanent teeth are sometimes less than usual, in conse- 
quence of the non-developement of the wisdom teeth, which re- 
main locked up in the jaw, and occasionally produce pain, and 
even abscesses in the bony structure. 

— Sometimes there are supernumerary teeth. Haller has seen 
in an infant of fourteen years, seventy-two teeth, thirty-six in 
each jaw, which appeared to depend upon a greater number than 
usual of the dental germs. Some, fond of the marvellous, have 
described the eruption of a third set of teeth analogous to the 
two first : but according to Hudson and others, this appearance 
has probably been owing to the tardy removal of the deciduous 
set, and the late supplial of their place by the permanent teeth. 
— Sometimes the direction of the teeth is vicious, leading into 
the ramus of the jaw, or upon the outer or inner surface of the 
gums ; or upon the roof of the mouth. Accidental developements 
of teeth have likewise been met with in the orbit, the tongue, 
pharynx, stomach, and not unfrequently in the ovaries and 
uterus. — 

Os Hyoides. 

The os hyoides is a small insulated bone, supported between the 
lower jaw and the larynx, by muscles and ligaments, which pro- 
ceed from the neighbouring parts in various directions. 

The figure of this bone, as its name imports, resembles the 
Greek letter u. In its natural situation, the central and convex 
part is anterior, and the lateral portions extend backwards. 

The central part is called the body, and the lateral portions the 
cornua. 

The body is broad and its upper edge bent inwards, so that the 
external surface is convex, vertically, as well as horizontally. On 
this surface is a horizontal ridge: the muscles which proceed 
from the lower jaw are generally inserted above this ridge, and 
the muscles from the sternum and scapula below it. 

The internal or posterior surface of the body is very concave. 

The cornua, in young subjects, are distinct from the body of 
the bone, and joined to it by cartilages: near the body of the os 



Ifjg ORBIT OF THE EYE. 

hyoides they are flat; but their figure soon changes, and they ter- 
minate on each side in a small tubercle. 

On the upper edge of the bone, where the cornua unite to the 
body, is a process, equal in size to a small grain of wheat, which 
has a direction upwards and backwards; this is called the appen- 
dix, or lesser cornu of the os hyoides: from it proceeds a liga- 
ment which is attached to the styloid process of the temporal 
bone, and is sometimes ossified. 

The basis of the tongue is attached to the os hyoides, and the 
motions of the bone have a particular reference to those of that 
organ; but they will be better understood when the parts with 
which it is connected have been described. 



An acquaintance with the individual bones which compose the head is 
principally useful, as it leads to a perfect understanding of the whole 
structure, of which each bone is but a small part. 

This structure comprises the cavities which contain the brain and the most 
important organs of sense, as well as the foramina subservient to them, 
which are of so much importance in the practice of medicine and surgery, 
and also in physiology, that the following descriptions are subjoined. 

Orbit of the Eye. 

The figure of this cavity is that of a quadrangular pyramid 
with its angles rounded ; so that it resembles a cone, the bottom 
being the apex and the orifice the base. 

The diameter of the cavity passes obliquely outward from the 
apex behind. As the figure is irregular, the side next the nose 
does not partake of this general obliquity, but extends in a straight 
direction from behind forwards. 

The orbit is somewhat contracted at its orifice, and enlarged 
immediately within. The form of the orifice is rather oval, as 
the transverse diameter is longer than the vertical. Seven bones 
are concerned in the formation of this cavity; the os frontis and 
a portion of the lesser wing of the sphenoid bone above the os 
planum or ethmoid, the os unguis, and the nasal process of the 



ORBIT OP THE EYE. iq~ 

upper maxillary bone, and the os palati below ; the os malas, and 
orbitar plate of the sphenoid bone, on the outside. 

On the upper surface is the depression for the lachrymal gland ; 
and at the orifice is the notch or foramen for the supra-orbitary 
vessels, &c. which have already been mentioned. 

On the inner surface are two longitudinal sutures, which con- 
nect the os planum and the os unguis to the os frontis above, and 
the os maxillare below. In the upper suture are the two internal 
orbitary foramina mentioned in the description of the os frontis, 
the anterior of which transmits a fibre of the ophthalmic nerve, 
with an artery and vein ; the posterior transmits only an artery 
and vein. There are also two smaller vertical sutures on each 
side of the os unguis. On the anterior part of this inner surface 
is the ridge of the os unguis, and the grooves for accommoda- 
ting the lachrymal sac, which passes into the canal of the same 
immediately below. 

On the lower surface is the aforesaid canal, formed by the nasal 
and orbitar process of the upper maxillary bone, and that part 
of the os unguis which is anterior to the ridge. On the poste- 
rior part of this surface is a groove which proceeds forwards, 
and penetrating into the bone, becomes a canal that terminates in 
the infra-orbitar foramen; this groove in the bone is made a 
canal by the periosteum. The thin plate which forms this surface 
is the partition between the antrum maxillare and the orbit of 
the eye, and is more or less absorbed in those cases where po- 
lypi of the antrum maxillare occasion a protrusion of the eye. 

The external surface, formed by the malar bone and the orbi- 
tar plate of the sphenoid, is almost fiat. In the posterior part of 
the orbit it is bounded by two large fissures, which are now to be 
described. 

In the posterior part of the orbit are three apertures. The 
optic foramen, the sphenoidal fissure, and the spheno-maxillary 
fissure. 

The optic foramen opens almost at the bottom of the orbit on 
the inside; its direction is forwards and outwards. 

The sphenoidal fissure, formed principally by the lesser and 
greater wings of the sphenoidal bone, begins at the bottom of 



108 CAVITIES OF THE NOSE. 

the orbit, and extends forward, upward, and outward. It is 
broad at the commencement, and gradually diminishes to a fis- 
sure. This fissure opens directly into the cavity of the cranium, 
and admits the third, fourth, sixth, and one branch of the fifth pair 
of nerves, an artery, and a vein. 

The spheno-maxillary fissure commences also at the bottom of 
the orbit, and extends forward, outward, and downward, be- 
tween the maxillary bone and the orbitar plate of the sphenoid, 
from the body of the sphenoid to the malar bone. This fissure 
opens from the orbit directly into the zygomatic fossa. In the re- 
cent subject it is closed, and only transmits the infra-orbitary 
nerve and vessels, and a small branch of the superior maxillary 
nerve. 

The Cavities of the Nose. 

These cavities, which are separated from each other by the 
septum narium,are contained between the cribriform plate of the 
ethmoid and the palatine process of the upper maxillary and pa- 
late bones, and between the anterior and posterior nares. They 
are, therefore, of considerable extent in these directions; but the 
distance from the septum to the opposite side of the nose is so 
small, that each cavity is very narrow. 

The upper surface of each cavity consists of that portion of 
the cribriform plate of the ethmoid which is between the septum 
and the cellular portions. Anterior to this, each cavity is bound- 
ed by the internal surface of the os nasi of its respective side ; 
and posterior to it, by the anterior surface of the body of the sphe- 
noid bone. These anterior and posterior surfaces form obtuse 
angles with the upper surface of the nose, and are immediately 
above the openings called anterior and posterior nares. The an- 
terior surface partakes of the figure of the os nasi ; the upper 
surface has the perforations of the cribriform plate ; the posterior 
surface has an opening, equal in diameter to a small quill, that 
leads into the sphenoidal cell, and it is also broader than the an- 
terior or superior surface. 

The internal surface, formed by the septum of the nose, which 
is composed of the vomer, the nasal plate of the ethmoid, and 



CAVITIES OF THE NOSE. 



109 



cartilaginous plate, is flat, but rather inclined to one side or the 
other, so as to make a difference in the nasal cavities. 

The external surface is very irregular ; it is formed by the cel- 
lular portions of the ethmoid ; by a small portion of the os un- 
guis ; by the upper maxillary bone ; the os turbinatum inferius ; 
the os palati ; and the internal pterygoid process of the os sphe- 
noides. The upper part of this surface is formed by the internal 
surface of the cellular portions of the ethmoid, which have been 
described at page 68. It extends from the sphenoid bone, very 
near to the ossa nasi ; and is uniformly flat and rough. 

About the middle of it begins a deep groove, which penetrates 
into the cellular structure of the ethmoides, and passes obliquely 
downwards and backwards. At the upper end of this groove is 
the foramen by which the posterior ethmoidal cells communicate 
with the nasal cavity. 

This is the upper channel or meatus of the nose. At the pos- 
terior end of it is a large foramen formed by the nasal plate of 
the os palati and the pterygoid process of the os sphenoides, and 
therefore- called pterygo or spheno-palatine foramen. It opens 
externally, and transmits a nerve and an artery to the nose. 

Below the meatus is the upper spongy bone, which presents a 
convex surface ; its lower edge is rolled up and not connected 
with the parts about it. This spongy bone covers a foramen in 
the ethmoid bone, by which its anterior cells and the frontal si- 
nuses communicate with the nose. 

Below this spongy bone is the middle channel, or meatus of the 
nose. The channel extends from the anterior to the posterior 
part of the cavity. It is very deep, as it penetrates to the max- 
illary bone. The cells of the ethmoid are above it ; the inferior 
turbinated bone below it ; and the upper spongy bone projects 
over it. In this channel is the opening of the great cavity of the 
upper maxillary bone. At the anterior extremity of it is a small 
portion of the os unguis, which intervenes between the nasal pro- 
cess of the upper maxillary bone and the cells of the ethmoid, 
and continues down to the lower spongy bone. 

The lower spongy bone is nearly horizontal, and very conspicu- 
vol. i. 10 



J JQ CAVITY OF THE CRANIUM. 

ous. It extends almost from one opening of the nose to the other. 
Under this bone is the third and largest channel or meatus of the 
nose. It is made large by an excavation of the upper maxillary- 
bone, particularly at the anterior part. It affords a direct and 
very easy passage to the posterior opening of the nose and the 
throat. 

Near the anterior extremity of this meatus is the lower orifice 
of the lachrymal duct, which is so situated that a probe properly 
curved can be readily passed into it through the nostril. 

There are, then, four foramina on each side, which form com- 
munications between the cavities of the nose and the adjacent 
cells, viz. 

One in the upper meatus, which leads to the posterior ethmoid 
cells. 

A second in the middle meatus, which leads to the anterior 
ethmoid cells and the frontal sinuses. 

A third in the same meatus, which opens into the maxillary 
sinus. 

A fourth in the anterior surface of the body of the sphenoidal 
bone, which opens into the sphenoidal sinus. 

To these must be added the opening of the lachrymal canal. 

It will be useful to the student of anatomy, after placing three or four of the up- 
permost cervical vertebrae in their natural situation, to take a view of 

The Cavity between the spine and the posterior JVares, which is 
bounded above, by the cuneiform process, passing obliquely up- 
ward and forward ; laterally, by soft parts not yet described ; 
behind, by the bodies of the cervical vertebrae ; and before, by 
the posterior nares, each of which is oblong in form, rounded 
above, flat below, and separated from the other by a thin parti- 
tion, the vomer. 

The Cavity of the Cranium.. 

The upper concave surface of this cavity corresponds with 
the figure of the cranium. The ridge in it for supporting the 
falciform process of the dura mater, the groove made by the 
longitudinal sinus, the impressions of the arteries, and the pits 



BASIS OF THE CRANIUM. 



Ill 



made by the convolutions of the brain, are particularly to be 
noticed. 

The Basis of the Cranium 

Is much more important. It is divided into three fossa? on each 
side ; the anterior of these are most superficial, and the posterior 
the deepest. The bottoms of the anterior fossce are formed bv 
the orbitar processes of the osfrontis, and consequently are con- 
vex; between them is the cribriform plate of the ethmoid, which 
is commonly sunk below the adjoining surface. The crista galli 
is very conspicuous ; and the foramen caecum can almost always 
be seen. The crista galli is evidently the beginning of the pro- 
minent ridge, which continues on the os frontis, and supports the 
falx of the dura mater. The posterior margins of these fossa- 
are formed by the lesser wings of the sphenoid bone. 

The middle fossce are formed by the great wings of the 
sphenoidal bone, and by the squamous and petrous portions of 
the temporal bone. They are lower than the anterior, and 
higher than the posterior fossae. The projection of the margin 
of the anterior fossae into these cavities, corresponds with the 
separation between the anterior and middle lobes of the brain. 
The suture between the sphenoidal and temporal bones is evi- 
dent in these fossae. The upper surface of the body of the 
sphenoid bone, or the sella turcica is between them ; and all the 
peculiarities of its surface are very conspicuous. The first five 
foramina of the sphenoidal bone can be easily ascertained, and 
also, the anterior foramen lacerum and termination of the fora- 
men caroticum, with the impressions made by the carotid arte- 
ries on the sides of the sella turcica. The petrous portions of the 
temporal bones are the posterior boundaries of the middle fossae. 
Their oblique direction, inwards and forwards, is particularly 
remarkable ; being formed like triangular pyramids. Two of 
their sides are in the cavity of the cranium ; one, which is ante- 
rior, forms a portion of the middle fossa ; and the other forms a 
part of the posterior fossa. The edge between them is very 
prominent, and has the tentorium or horizontal process of the 
dura mater attached to it. On the anterior surface, in the mid- 



112 BASIS OF THE CRANIUM. 

die fossa, may be traced the groove, and the foramen for the 
Vidian nerve. 

The posterior fossae are larger as well as deeper than the other 
two. Their boundaries are well defined by the edges of the 
petrous bones above mentioned, and by the grooves of the hori- 
zontal parts of the lateral sinuses. These fossae are nearly 
separated from the general cavity by the tentorium, which is 
attached to the edge of the petrous bone and also to the edge of 
the horizontal part of the groove for the lateral sinuses. On the 
tentorium lie the posterior lobes of the cerebrum ; and under it, 
in these fossae, is the cerebellum. 

These fossae may be considered as one great cavity, which is 
circular behind, and somewhat angular before. The angular 
surfaces are formed by the posterior sides of the petrous portions. 
Between them, is the oblique surface of the cuneiform process of 
the occipital bone, which descends to the great foramen. On 
the surface of each petrous bone is the meatus auditorius internus, 
and the orifice of the aqueduct of the vestibule. Behind the 
petrous portion, the groove for the lateral sinus is very conspi- 
cuous ; it terminates in the posterior foramen lacerum, which is 
evidently formed by the temporal and the occipital bones. At 
the anterior part of this foramen is most commonly a small 
bony process, which separates the eighth pair of nerves from 
the internal jugular vein, as they pass out here. 

The anterior condyloid foramen for the passage of the ninth 
pair of nerves, appears in the surface of the great occipital hole, 
immediately below the foramen lacerum. From the back part 
of this hole the spine, which forms the lower limb of the cross, 
passes up; and on each side of it are the great depressions 
which accommodate the two lobes of the cerebellum. 

External Basis of the Cranium. 

When the head is inverted, we see the external protuberances 
of the os occipitis, formerly described. The mastoid processes 
of the ossa temporum are on the same transverse line with the 
great foramen of the os occipitis ; but the foramen being larger 
extends farther forward. On the inside of the mastoid process, 



BASIS OF THE CRANIUM 



113 



ihe fissure for the digastric muscle is very conspicuous, and 
also the suture between the mastoid process and the occipital 
bone. 

The oblique direction of the occipital condyles and the slant- 
ing position of their articulating surfaces are particularly striking. 
The posterior condyloid foramina for the cervical veins, and the 
anterior for the ninth pair of nerves, are also in view. The posi- 
tion of the cuneiform process of the os occipitis is by no means 
horizontal, but extends forwards and upwards. The petrous or 
pyramidal -portion of the temporal bone commences between the 
mastoid process and the condyle of the lower jaw, and extends 
obliquely forwards and inwards, having the occipital bone behind 
it, and the glenoid cavity and the os sphenoides before it. At the 
commencement, the surface of the petrous portion is not horizon- 
tal, but oblique, sloping into the glenoid cavity with a sharp edge 
downwards. This edge in some cases is curved so as to sur- 
round the basis of the styloid process, which arises in contact 
with it, and projects downwards, on each side of the vertebra?. 
Between the mastoid and styloid process, is the foramen stylo- 
mastoideum. On the inside of the styloid process, and rather 
anterior to it, is the foramen lacerum posterius, for the internal 
jugular vein, the eighth pair of nerves, &c. This foramen passes 
obliquely backwards and upwards, and is bounded behind by the 
jugular process of the os occipitis, which bone seems to contri- 
bute most to its formation. Very near to this hole on the inside 
is the anterior condyloid foramen ; and rather anterior to it is 
the opening of the carotid canal, which forms a curve in the 
bone as it passes upwards, inwards, and forwards. 

From the foramen lacerum posterius, the suture between the 
cuneiform process of the occipital and the petrous portion of the 
temporal bone, extends to the foramen lacerum anterius ; which 
is closed by cartilage in the recent subject, but is of an irregular 
and rather triangular form in the macerated head ; this hole is 
formed by the occipital, sphenoidal, and petrous bones. The 
suture or connexion between the petrous bone and the os sphe- 
noides, is continued on the anterior side of the petrous bone, 
from the fissure of the glenoid cavity to the anterior foramen 

10*" 



1 14 SIDE 0F THE HEAD 

Jacerum. The styloid process of the os sphenoides, which is 
seldom more than four lines in length, appears at the edge of 
this suture. On the inside of the glenoid cavity, and on the in- 
side of this process, in the suture formed between the petrous 
and sphenoid bones, is the bony orifice of the Eustachian tube. 

The foramen spinale, for the middle artery of the dura mater, 
is at a very small distance from the Eustachian tube, imme- 
diately anterior to it ; and at a small distance on the inside and 
front of this foramen is the foramen ovale, for the inferior maxil- 
lary nerve, or the third branch of the fifth pair. 

Side of the Head. 

Those portions of the side of the head which are formed by 
the frontal, parietal and occipital bones, and by the squamous 
part of the temporal, require no explanation here ; but the region 
which is behind the malar and upper maxillary bone, and within 
the zygomatic processes of the temporal and malar bones, which 
comprises part of the temporal and zygomatic fossa? of some 
anatomists, is both important and obscure. 

To obtain a view of this, the lower jaw should be removed, 
and the zygoma sawed away, in one preparation; and in an- 
other, the upper maxillary and palate bones of one side should be 
applied in their natural position, to the os sphenoides, without any 
of the other bones. 

The upper part of this region, formed by the sphenoidal, 
frontal and malar bones, is made concave by the form of the 
external angular part of the os frontis and of the os mala? ; which 
projects backwards so as to cover a large portion of it. 

The lower part is formed principally by the external surface 
of the pterygoid process of the sphenoid bone, and by the poste- 
rior surface of the upper maxillary. Between the lower end of 
the pterygoid process and the upper maxillary bone, a small 
portion of the os palati intervenes; but in many adult subjects it 
is not to be distinguished from the other bones. At this place, 
the pterygoid process and these bones appear to be in close con- 
tact ; but as they pass upwards they recede from each other so 
as to form a considerable aperture, which continues the whole 



FORM OF THE CRANIUM. 



115 



length of the pterygoid process. This fissure, which may be 
called pterygo-palatine or ptery go-maxillary, would open into the 
posterior part of the cavity of the nose, if the nasal plate of the 
os palati did not intervene ; this plate forms a partition, which 
separates the nose from this fissure : and the spheno-palatine 
foramen, formed principally by it, transmits a nerve and blood- 
vessels to the nose. 

The fissure is vertical : at the back of the orbit, it unites with 
the spheno-maxillary fissure of the orbit, which is almost hori- 
zontal, and at the place of their junction, the sphenoidal, or upper 
fissure of the orbit, opens also. 

The foramen rotundum, which transmits the second branch 
of the fifth pair, or the upper maxillary nerve, is likewise situated 
near this place ; and when the upper maxillary, the sphenoidal, 
and the palate bones are in their natural situation, the distribu- 
tion of the branches of this important nerve can be easily under- 
stood : for the same view presents the course of its various 
branches ; viz. to the nose, by the spheno-palatine foramen ; to 
the cavity of the cranium, by the pterygoid foramen; to the orbit, 
and the inferior orbitary canal, by the spheno-maxillary fissure ; 
and to the roof of the mouth, by the palato-maxillary canal. 

The Form of the Cranium. 

The form of the cranium is that of an irregular oval. The 
greatest length of its cavity is between a part of the os frontis 
above the crista galli, and of the os occipitis above the centre of 
the crucial ridge. 

The greatest breadth is at about two-thirds of the distance 
from the first to the last of these positions. This transverse 
diameter touches the sides of the cranium near the posterior 
part of the basis of the petrous portion of the temporal bone. 
The difference between these longitudinal and transverse diame- 
ters varies greatly in different persons, as their craniums ap- 
proach to the oval or round figures. 

The greatest depth of the cavity is between the posterior part 
of the cuneiform process of the occipital bone, and a part of the 



116 FORM OF THE CRANIUM. 

cranium which is nearly over it about the middle of the sagittal 
suture. 

The figure of the cranium is somewhat varied in different 
races of men ; and it has been much changed by the particular 
management of several savage nations. 

In North America, the Choctaw tribe of Indians were for- 
merly accustomed to make their foreheads perfectly flat, and 
sloping obliquely backwards. They have latterly disused this 
practice; but one of their nation, whose head had this form, was 
in Philadelphia about the year 1796. 

At this time a tribe who inhabit a district of country near the 
sources of the Missouri river, are in the practice of flattening 
both the frontal and occipital regions of the head ; so that a 
small part only, of the middle of it, remains of the natural form, 
between these flattened sloping surfaces. 

In the case of the Choctaw man above-mentioned, it did not 
appear that his health, or his intellectual operations, were any 
w r ay affected by this form of his head. 

During infancy, the cranium sometimes increases to a preter- 
natural size, as disproportionate to the face as if it were affected 
by hydrocephalus. In many of these instances, that disease ulti- 
mately shows itself; but in other cases, the preternatural increase 
of the cranium finally stops without the occurrence of disease ; 
and the disproportion is lessened by the increase of the face in 
the ordinary progress of growth. 

In many cases where men have deviated from the ordinary 
stature, the head has preserved the common size. It is there- 
fore said to be small in giants, and large in dwarfs. 

— Many efforts have been made to determine rigorously the di- 
mensions of the cavity of the cranium. This may be done with 
considerable accuracy from the exterior of the skull, by making 
allowances for the various degrees of developement in which the 
frontal sinuses are found in different individuals. The thickness 
of the diploe seldom varies in different skulls more than one or 
two lines in thickness. There is, however, a skull (a black,) in 
the possession of Dr. Parrish of this city, the walls of which are 
nearly three-quarters of an inch in thickness, and so compact in 



FACIAL AND OCCIPITAL ANGLES. 



117 



its composition as to present very little of the diploic or cellular 
structure. When measured from the interior, a skull of ordinary 
capacity will measure in its longitudinal diameter, (between the 
frontal spine and longitudinal sulcus,) five inches and a half; in 
its transverse, (between the bases of the petrous portions of the 
temporal bones,) four and a half; between the parietal fossse five 
inches, and between the lesser wings of the sphenoid bones, three 
inches and three-quarters ; in the vertical, from the foramen mag- 
num to the sagittal suture, four inches and a half. 
— Several plans have also been adopted, by the cranioscopists. 
to determine the relative developement of the cranium (which is 
filled with the brain) and that of the face. The best known of these 
are those of Camper, Daubenton and Cuvier. The facial angle 
of Camper, is taken by extending a horizontal line from the ex- 
ternal auditory meatus, on a line with the floor of the nostrils, so 
as to follow nearly the direction of the base of the cranium, and 
by dropping upon this a second from the most prominent part of 
the forehead to the extremity of the upper jaw. The area be- 
tween them is the facial angle, and will be the more acute, in 
direct proportion as the face is developed in front, and the fore- 
head is sloped backwards. This angle is of course larger in 
man than in any other animal, and varies in size in the different 
races of men. In a well formed white or Caucasian, it is usually 
about 80°; in the Mongolian about 75°; in Negroes about 70°; 
in the different species of monkeys it varies from 65° to 30°. As 
a test of the intellectual capacity of individuals, it is but little to 
be relied on. 

— The occipital angle of Daubenton, is formed by drawing two 
lines* one from the inferior border of the orbit, to the anterior 
margin of the occipital foramen, the other drawn from the ante- 
rior to the posterior border of the occipital foramen, and extend- 
ed forwards. The angle between the two, is the occipital. As 
the direction of the occipital foramen depends upon the manner 
in which the head is articulated with the vertebral column, it 
will be the larger, the less favourably the animal is constructed 
for the upright posture. In a well formed Caucasian skull, it is 
about 3°. In the ox it is about 70°. Daubenton has thus done 



119 HEAD OP THE F(ETUS. 

for the posterior part of the head what Camper has done for the 
anterior. 

— Cuvier's method consists in dividing the skull vertically, and 
establishing a comparison between the area of the cranium and 
that of the face. In a well formed Caucasian he finds the area 
of the cranium, quadruple that of the face. In the Mongolian 
variety, he found the area of the face had increased over this 
proportion one-tenth, in the Negro, one-fifth ; in monkeys one- 
half. Tiedemann has adopted a plan of measuring the capacity 
of different crania, by filling them with seeds from the occipital 
foramen, and subsequently measuring their contents. This me- 
thod as well as some others, has been applied by Dr. S. G. Mor- 
ton of this city, in a forthcoming very scientific work on the 
Crania Americana, so as to leave henceforth little to be wished 
upon a subject which has excited much interest among physiolo- 
gists. The whole capacity of the cranium is found on an ave- 
rage, greater in the Caucasian variety of the human race, than 
in any other. 

The Head of the Fastus. 

In the foetus, these bones, which form the vault of the cra- 
nium, originally consist of one plate only; which is composed o 
radiant fibres. 

At birth, the osfrontis consists of two pieces, which join each 
other in the middle of the forehead. 

The parietal bones are each in a single piece ; but they are 
incomplete at their edges and their angles. 

The temporal bones have no appearance of mastoid or styloid 
processes. Instead of a meatus auditorius externus, there is a 
bony ring in which the membrana tympani is fixed. The 
squamous and petrous portions, and this ring, are originally 
formed separate ; but at the period of birth they often adhere to 
each other. 

The os occipitis is composed of four pieces: the first and 
largest, extends from the beginning or angle of the lambdoidal 
suture to the upper edge of the great occipital foramen. Each 
side of the foramen, and the condyle on it, is formed by a dis- 



HEAD OF THE FCETUS. i jg 

tinct piece. The front part is formed by the cuneiform process, 
which is separate from the other parts and forms the fourth 
piece. 

The sphenoidal bone may be separated by maceration into 
three pieces. The body and the little wings form one piece. 
Each of the great wings, with the pterygoid processes united to 
it, forms also a piece. The body of the bone is entirely solid. 

A large part of the ethmoid is in a cartilaginous state. It is 
divided into two portions by a partition of cartilage, which occu- 
pies the place of the nasal plate and the crista galli. 

In consequence of the imperfect formation of the bones which 
compose the vault of the cranium, there are several deficiencies 
in it. Thus the superior anterior angles of the parietal bones 
being incomplete, and also the upper angles of the pieces which 
compose the os frontis, a vacuity with four sides is occasioned, 
which is termed the 

Anterior fontanel. This opening may be distinguished by its 
form, as well as its greater size, from another vacuity which is 
produced in a similar way at the other end of the sagittal suture, 
and called the 

Posterior fontanel: but as there are only three bones con- 
cerned in its formation, viz. the two parietal and the occipital, 
this vacuity is triangular. 

Besides these, there are two other vacuities or fontanels on 
each side, at the two lower corners of each parietal bone : these, 
however, are much less than those first described. 

The smaller fontanels do not continue open long ; but the an- 
terior fontanel is seldom completely closed before the end of the 
third year. 

It is very obvious, upon an examination of the cranium, that 
the centre of the base is better calculated to resist pressure than 
any other part ; as the cuneiform process of the occipital bone, 
the petrous portions of the temporal, and the body of the sphe- 
noidal bone, which compose a large part of it, are very firm and 
substantial. 

The face of the foztus differs very essentially from that of the 
adult. Although the orbits of the eyes are very large when 



120 OF THE SPINE. 

compared with the size of the head, that portion of the face 
which is below them is very small, and has little depth. 

The upper maxillary bones have no sinuses in them; and their 
orbitar plates are not much elevated above the cavities for con- 
taining the posterior teeth ; in consequence, the depth of the face 
is very small, and its whole aspect is affected. 

The nose of the foetus differs greatly from that of the adult in 
respect to its sinuses; for not only are the maxillary cavities 
wanting, but those of the frontal and sphenoidal bones also. 

The lower jaw is formed in two pieces, which unite at the 
middle ; and hence the term symphysis is used in describing the 
chin. The bone is not only less broad in proportion than that 
of the adult, but the angles are more obtuse, and the processes 
which arise from them are more sloping. 

The head of the foetus is much larger in proportion to the body 
than that of the adult. 

Of the Trunk. 
The Trunk consists of the Spine, Thorax, and Pelvis. 

The Spine. 

The spine is the long pile of bones extending from the con- 
dyles of the occiput to the end of the os coccygis. It somewhat 
resembles two unequal pyramids joined in a common base. It 
is not, however, straight ; for its upper part being drawn back- 
wards by strong muscles, it gradually advances forwards to sup- 
port the oesophagus, vessels of the head, &c. Then it turns 
backwards, to make room for the heart and lungs. It is next 
bent forwards to support the viscera of the abdomen. It after- 
wards turns backwards for the enlargement of the pelvis. And. 
lastly, it is reflected forwards, for sustaining the lowest great 
intestines. 

The spine is commonly divided into true and false vertebra; 
the former constituting the long upper pyramid, which has its base 
below ; while the false vertebras make the shorter lower pyra- 
mid, whose base is above. 



THE VERTEBRAE. 



121 



True Vertebra. 

The true vertebra: are the twenty -four upper bones of the spine, 
on which the several motions of the trunk of our bodies are per- 
formed. Their name is derived from the Latin verb verterc. 

Each of these vertebras is composed of its body and pro- 
cesses. 

The body is the thick spongy forepart, which is convex before, 
concave backwards, horizontal and flat in most of them above 
and below. Numerous small holes, especially on the fore and 
back part of their surface, giving passage to their vessels, and 
allow the ligaments to enter their substance. The edges of the 
body of each vertebrae are covered, especially at the forepart, 
with a ring of bone firmer and more solid than the substance of 
the body any where else. These rings seem to be joined to the 
vertebras in the form of epiphyses. They are of great use in 
preventing the spongy bodies from being broken in the motions 
of the trunk. 

Between the bodies of each two adjoining vertebras, a sub- 
stance between the nature of ligament and cartilage is inter- 
posed; which seems to consist of concentrical curved fibres, when 
it is cut horizontally; but when it is divided perpendicularly, the 
fibres appear oblique and decussating. The outer part of these 
intervertebral ligaments is the most solid and hard ; and they 
gradually become softer till they are almost in the form of a 
glairy liquor in the centre. The external fibrous part of each 
is capable of being greatly extended, and of being compressed 
into a smaller space, while the middle fluid part is incompres- 
sible, or nearly so. The middle point is therefore a fulcrum or 
pivot, on which the motion of a ball and socket may be made, 
with such a gradual yielding of the substance of the ligament, 
in whatever direction our spines are moved, as saves the body 
from violent shocks, and their dangerous consequences. This 
ligamento-cartilaginous substance is firmly fixed to the horizon- 
tal surfaces of the bodies of the vertebras, to connect them ; in 
which it is assisted by a strong membranous ligament, which 

VOL. I. 11 



j 22 TH£ VERTEBRAE 

lines all their concave surface, and by a still stronger ligament 
that covers all their anterior convex surface. 

The elastic substance seems to be in a state of compression by 
the exterior ligament and the bones ; for, if a section be made 
through a portion of the vertebras and the intervertebral sub- 
stance, this substance will expand, so that its surface will be 
much higher than that of the vertebrae. It is so elastic, and so 
much confined, in some subjects, that a sharp knife, if plunged 
into it will be gradually ejected when the hand is withdrawn. 

The bodies of the vertebrae are, with some exceptions, smaller 
and more solid above, but more spongy as they descend. The 
cartilages between them are thick, and the surrounding liga- 
ments are strong in proportion to the size of the vertebrae. By 
this disposition, the greatest weight is supported on the broadest, 
best secured base, and the middle of the body is allowed a large 
and secure motion. 

From each side of the body of each vertebrae, a bony bridge 
is produced backwards, and to one side ; from the posterior end 
of which one slanting process rises, and another descends. The 
smooth, and generally the flattest side of each of these four pro- 
cesses is covered with a smooth cartilage ; and the two lower 
processes of each upper vertebrae are fitted to and articulated with 
the two upper processes of the vertebras below, having their ar- 
ticular ligaments fixed into the rough line round their edges. 
These processes are termed the oblique or articulating. 

From between the oblique processes of each side, another pro- 
cess extends laterally, which is called the transverse. 

From the back part of the roots of the two oblique processes, 
and of the transverse process of each side, a broad oblique bony 
plate is extended backwards : where these meet, the seventh pro- 
cess of the vertebras takes its rise, and stands out backwards. 
This being generally sharp-pointed and narrow-edged, it has 
therefore been called spinal process; from which this whole 
chain of bones has got its name. 

Besides the common ligament which lines all the internal sur- 
face of the spinal processes as well as of the bodies, particular 



THE VERTEBRAE. j^3 

ligaments connect the bony bridges and processes of the conti- 
guous vertebrae together. 

The substance of the processes is considerably stronger and 
firmer, and has a thicker external plate than the bodies of the 
vertebrae themselves. 

The seven processes form a concavity at their forepart, which, 
joined to the one at the back part of the bodies, make a great 
hole ; and when the vertebrae are placed upon each other in their 
natural order, these holes form a long tube for containing the 
spinal marrow. 

In the upper and lower edge of each lateral bridge, there is a 
notch. These are so adapted to each other in the contiguous 
vertebrae, as to form a round hole in each side, between each two 
vertebrae, through which the nerves proceed from the spinal mar- 
row, and its blood-vessels pass. 

The articulations of these two vertebrae are consequently 
double; for their bodies are joined by the intervening cartilage 
above described ; and their oblique processes, being tipped with 
cartilages, are so connected by their ligaments as to allow at 
small degree of motion on every side. Hence, it is evident that 
their centre of motion is altered in different positions of the 
trunk : for, when we bow forwards, the weight bears entirely on 
the bodies of the vertebrae ; if we bend back, the oblique pro- 
cesses support it ; if we recline to one side, we rest upon the 
oblique processes of that side and part of the bodies ; if we stand 
erect all the bodies and oblique processes have their share in our 
support. 

The true vertebra are divided into three classes, which agree 
with each other in their general structure, but are distinguished 
by several peculiarities. 

These classes are named Cervical, Dorsal, and Lumbar. 
The cervical are the seven uppermost vertebrae ; which are 
distinguished from the rest by these marks: their bodies are 
smaller and more solid than any others ; and are flattened on 
the front surface. They are also flat behind, where small pro- 
cesses rise, to which the internal ligaments are fixed. The up- 



j 24 CERVICAL VERTEBRAE. 

per surface of the body of each vertebras is made hollow, by a 
slanting thin process which is raised on each side. The lower 
surface is also hollowed, but in a different manner ; for here the 
posterior edge is raised a little, and the anterior one is consider- 
ably extended. Hence, the cartilages between these vertebrae 
are firmly connected, and their articulations are secure. 

These cartilages are thick, especially at their forepart ; which 
is one reason why the vertebras project forward as they descend, 
and" have the larger motion. 

Their oblique processes more justly deserve that name than 
those of any other vertebras. They are situated slanting ; the 
upper ones having their smooth and almost flat surfaces facing 
obliquely backwards and upwards ; while the inferior oblique 
processes have these surfaces facing obliquely forwards and 
downwards. 

The transverse processes of these vertebrae are framed in a dif- 
ferent manner from those of any other bones of the spine ; for, 
besides the common transverse process rising from between the 
oblique processes of each side, there is a second one that comes 
out from the side of the body of each vertebrae ; and these two 
processes, after leaving a circular hole for the passage of the 
vertebral artery and vein, unite and form a groove on their up- 
per surface to protect the nerves that pass in it. They termi- 
nate obtusely on each side, for the insertion of muscles. 

The spinal processes project backwards almost horizontally. 
They are shorter than those of any other vertebras, and are 
forked or double at their ends ; they therefore allow a more con- 
venient insertion to muscles. 

The thick cartilages between the bodies of these cervical ver- 
tebras, the obliquity of their oblique processes, and the shortness 
and horizontal situation of their spinal processes, all conspire to 
allow them large motion. 

The holes between the bony cross bridges, for the passage of 
the nerves from the spinal marrow, have their largest share 
formed in the lowest of the two vertebras, to which they are 
common. 



CERVICAL VERTEBRAE. J 25 

So far most of the cervical vertebrae agree ; but they have 
some particular differences, which require a separate conside- 
ration. 

The first, from its use in supporting the head, has the name of 
atlas. Contrary to all the other vertebras of the spine, it has no 
body; but, instead of it, there is a bony arch. In the convex 
forepart of this arch a small rising appears; and on each side of 
this protuberance, a small cavity may be observed. The upper 
and lower parts of the arch are rough and unequal, where the 
ligaments that connect this vertebra to the os occipitis, and to 
the second vertebra, are fixed. The back part of the arch is 
concave, smooth, and covered with a cartilage, in a recent sub- 
ject, to receive the tooth-like process of the second vertebra. 
On each side of it a small rough sinuosity may be remarked, 
where the ligaments going to the sides of the tooth-like process 
of the following vertebra are fastened ; and on each side a small 
rough protuberance and a depression is observable, where the 
transverse ligament, which secures the tooth-like process in the 
sinuosity, is fixed, and hinders that process from injuring the me- 
dulla spinalis in the flexions of the head. 

The atlas has as little spinal process as body ; but, instead of 
it, there is a large bony arch, that the muscles which pass over 
this vertebra at that place might not be hurl in extending the 
head. On the posterior and upper part of this arch, there are 
two depressions, where the recti postici minores muscles take 
their rise ; and at the lower part are two other sinuosities, into 
which the ligaments that connect this bone to the following one 
are fixed. 

The superior oblique processes, of the atlas are large, and more 
horizontal than those of any other vertebra. They form an ob- 
long concave surface which has an internal aspect, and corre- 
sponds exactly with the articulating surface on the external side 
of each condyle of the os occipitis. Under the external edge of 
the posterior part of each of these cavities is the fossa, or deep 
open channel, in which the vertebral arteries make the circular 
turn, as they are about to enter the great foramen of the occipi. 

11 * 



j 05 CERVICAL VERTEBRAE. 

tal bone, and where the tenth pair of nerves go out. In some 
subjects, this fossa is covered with bone. The inferior oblique 
processes, extending from within outwards and downwards, are 
large, circular, and slightly concave. So that this vertebra, con- 
trary to the other six, receives the bones with which it is articu- 
lated, both above and below. 

The transverse processes of this vertebra are not much hol- 
lowed or forked ; but are longer and larger than those of any 
other vertebra? of the neck, for the origin and insertion of seve- 
ral muscles ; and, therefore, those muscles which move this ver- 
tebra on the second, have a considerable lever to act with, be- 
cause of the distance of their insertion from the axis of revolu- 
tion. 

The hole for the medulla spinalis is larger in the atlas than in 
any other vertebra, not only on account of the medulla being 
largest here, but also to prevent its being hurt by the motions of 
this vertebra on the second. This large hole, and the long trans- 
verse processes, make this the broadest vertebra of the neck. 

The condyles of the os occipitis move forwards and back- 
wards in the superior oblique processes of this vertebra ; but 
from the figure of the bones forming these articulations, it is 
evident that very little motion can here be allowed to either 
side ; and there must be still less circular motion. The second 
vertebra of the neck is called dentata. It is somewhat of a 
pyramidal figure, being large, and extended downwards, espe- 
cially in front, to enter into a hollow of the vertebra below ; 
while the upper part has a long process, with its extremity formed 
into an obtuse point. This process, from its supposed resemblance 
to a tooth, has given name to the vertebra. The side of it, on 
which the concave surface of the anterior arch of the first ver- 
tebra plays, is convex, smooth, and covered with a cartilage ; 
and it is of the same form behind, to accommodate the ligament 
which is extended transversely from one rough protuberance of 
the first vertebra to the other, and is cartilaginous in the middle. 
A ligament likewise goes out in an oblique transverse direction, 
from each side of the processus dentatus, to be fixed at its other 
end to the first vertebra, and to the occipital bone ; and another 



CERVICAL VERTEBRAE. J27 

ligament rises up from near the point of the process to the os 
occipitis. 

The superior oblique processes of the vertebra dentata are 
large, circular, very nearly in a horizontal position, and slightly 
convex, to be adapted to the inferior oblique processes of the 
first vertebra. The inferior oblique processes of this vertebra 
answer exactly to the description given of those common to all 
the cervical vertebrae. 

The transverse processes of the vertebra dentata are short, 
very little hollowed at their upper part, and not forked at their 
ends ; and the canals through which the vertebral arteries pass, 
are reflected outwards about the middle of each process, so that 
the course of these vessels may be directed towards the trans- 
verse processes of the first vertebra. Had this curvature of the 
arteries been made in a part so movable as the neck is, while 
they were not defended by a bone and placed in the cavity of 
that bone, scarce a motion could have been performed without 
the utmost hazard of compression. This is the third instance of 
similar mechanism in cases of sudden curvature of arteries. 
The first is the passage of the carotids through the temporal 
bones ; and the second is that lately described, where the verte- 
bral arteries turn round the oblique processes of the first verte- 
bra, to come at the great hole of the occipital bone. 

The spinal process of this vertebra is thick, strong, and short, 
to give sufficient origin to the musculi recti majores and obliqui 
inferiores, and to prevent the contusion of these and other mus- 
cles in pulling the head back. 

The four cervical vertebras which are next in order have 
nothing particular in their structure, but agree with the general 
description. The seventh vertebra approaches the form of those 
of the back, having the upper and lower surfaces less excavated 
than the others. The oblique processes are more perpendicular ; 
and the spinal as well as transverse processes are without bifur- 
cation. 

After an examination of the condyles of the os occipitis, and 
of the whole structure of the atlas and vertebra dentata, it will 



j 28 DORSAL VERTEBRA. 

be evident, that the flexion and extension of the head, or its mo- 
tion backwards and forwards, is effected by the movements of 
the condyles of the occipital bone on the atlas ; and that in the 
rotation of the head, the atlas revolves to a certain degree round 
the processus dentatus of the second vertebra : the head neces- 
sarily moving with it. 

The twelve dorsal may be distinguished from the other ver- 
tebra of the spine by the following marks. 

Their bodies are of a middle size, between those of the neck 
and loins. They are more convex before than either of the 
other two sorts; and are flattened laterally by the pressure 
of the ribs, which are inserted into small cavities formed in 
their sides. This flatness of their sides, which makes the figure 
of these vertebrae almost a half oval, is of great use ; as it af- 
fords a firm articulation to the ribs, allows the trachea arteria to 
divide at a small angle, and the other large vessels to run secure 
from the action of the vital organs. Their bodies are more con- 
cave behind than any of the other two classes. The upper and 
lower surfaces are horizontal. 

The cartilages interposed between the bodies of these verte- 
brae are thinner than in any other of the true vertebrae ; and 
contribute to the concavity of the spine in the thorax, by being 
thinnest at their forepart. 

The oblique processes are placed almost perpendicularly : the 
upper ones slanting but a little forwards, and the lower ones 
slanting as much backwards. The convexity or concavity is 
not so remarkable as to require particular notice. Between the 
oblique processes of opposite sides several sharp processes stand 
out from the upper and lower parts of the plates which join to 
form the spinal processes : into these sharp processes strong liga- 
ments are fixed for connecting the vertebrae. 

The transverse processes of the dorsal vertebrae are long, 
thicker at their ends than in the middle, and turned obliquely 
backwards, which maybe owing to the pressure of the ribs; 
the tubercles of which are inserted into a depression near the 
end of these processes. 



DORSAL VERTEBRA. 



129 



The spinal processes are long, small-pointed, and sloping down- 
wards and backwards. From their upper and back part a ridge 
rises, which is received by a small channel in the forepart of the 
spinal process immediately above, which is here connected to it 
by a ligament. 

The canal for the spinal marrow is here more circular, but 
corresponding to the size of that chord, is smaller than in any 
of the other vertebrae ; and a larger share of the holes in the 
bony bridges for the transmission of the nerves, is formed in the 
vertebra above than in the one below. 

The connexion of the dorsal vertebrae to the ribs, the thinness 
of their cartilages, the erect situation of the oblique processes, 
the length, sloping, and connexion of the spinal processes, all 
contribute to restrain these vertebrae from much motion, which 
might disturb the actions of the heart and lungs; and in conse- 
quence of the little motion allowed here, the intervertebral car- 
tilages sooner shrivel, by becoming more solid ; and therefore 
the first remarkable curvature of the spine observed, as people 
advance to old age, is in the least stretched vertebrae of the back: 
or old people first become round-shouldered. 

The bodies of the four uppermost dorsal vertebrae deviate from 
the rule, and the vertebrae become larger as they descend ; for 
the first of the four is the largest, and the other three below 
gradually become smaller, to allow the trachea and large vessels 
to divide at smaller angles. 

The two uppermost vertebrae of the back, instead of being 
very prominent forwards, are flattened by the action of the mus- 
culi longi colli and recti majores. 

The proportional size of the two little depressions in the 
body of each vertebra for receiving the heads of the ribs seems 
to vary in the following manner : the depression on the upper 
edge of each vertebra decreases as far down as the fourth, and, 
after that, increases. 

The transverse processes are longer in each lower vertebra to 
the seventh or eighth, with their smooth surfaces, for the tuber- 
cles of the ribs, facing gradually more downwards; but after- 



, on LUMBAR VERTEBRAE. 

wards, as they descend, they become shorter, and the smooth 
surfaces are directed more upwards. 

The spinous processes of the vertebras of the back become 
gradually longer and more slanting from the first, as far down as 
the eighth or ninth vertebra ; from which they manifestly turn 
shorter and more erect. 

The first vertebra, besides an oblong hollow in its lower edge, 
that assists in forming the cavity wherein the second rib is re- 
ceived, has the whole cavity for the head of the first rib formed 

in it. 

The eleventh often has the whole cavity for the eleventh rib 
in its body, and wants the smooth surface on each transverse 
process. 

The twelfth always receives the whole head of the last rib, 
and has no smooth surface on its transverse processes, which 
are very short. The smooth surfaces of its inferior oblique pro- 
cesses face outwards as the lumbar do. In general the upper 
vertebrae of the back lose gradually their resemblance to those 
of the neck, and the lower ones approach gradually to the figure 
of the lumbar. 

The lumbar vertebrae are five bones, that may be distin- 
guished from any others by these marks : 1. Their bodies, 
though of a circular form at their forepart, are somewhat oblong 
from one side to the other. The epiphysis on their edges are 
larger ; and therefore the upper and lower surfaces of their bo- 
dies are more concave than in the vertebrae of the back. 2. The 
cartilages between these vertebrae are very thick, and render 
the spine convex within the abdomen, by their great thickness 
anteriorly. 3. The oblique processes are strong and deep ; the 
superior, which are concave, facing inwards, and the convex 
inferior ones facing outwards ; and therefore each of these ver- 
tebrae receives the one above it, and it is received by the one 
below, which is not so evident in the other two classes already 
described. 4. Their transverse processes are small, long, and 
almost horizontal, for allowing large motion to each bone, and 
sufficient insertion to muscles, and for supporting and defending 



LUMBAR VERTEBRAE. 



131 

the internal parts. 5. Between the roots of the superior oblique 
and transverse processes, a small protuberance may be observed, 
where some of the muscles that raise the trunk of the body are 
inserted. 6. Their spinal processes are strong, straight, and 
horizontal, with broad flat sides, and a narrow edge above and 
below ; this last being depressed on each side, by muscles; and, 
at the root of these edges, we see rough surfaces for fixing the 
ligaments. 7. The medullary canal is larger in these bones than 
in the dorsal vertebrae. 8. The holes for the passage of the 
nerves are more equally formed out of both the contiguous ver- 
tebrae than in the other classes ; the upper one furnishes, how- 
ever, the larger share of each hole. 

The thick cartilages between these lumbar vertebrae, their 
deep oblique processes, and their erect spinal processes, are all 
fit for allowing large motion, though it is not so great as what is 
performed in the neck ; which appears from comparing the 
arches which the head describes when moving on the neck or 
the loins only. 

The lumbar vertebrae, as they descend, have their oblique 
processes at a great distance from each other, and facing more 
backward and forwards. 

The transverse and spinal processes of the first and last lum- 
bar vertebrae are shorter than those in the middle. 

The epiphyses round the edges of the bodies of the lumbar 
vertebrae are most raised in the two lowest; which consequent^ 
make them appear hollower in the middle than the others are. 

The body of the fifth vertebra is rather thinner than that of 
the fourth. The spinal process of this fifth is smaller, and the 
oblique processes face more backwards and forwards, than those 
of any other lumbar vertebrae. 

In consequence of this particular construction, the spine is 
capable of flexion, principally in an interior and lateral direction, 
and also of extension. It ought to be remarked, that during 
flexion it forms a curve, and not an angle; for, in the last case, 
the spinal marrow would be more or less compressed. 

The cervical vertebrae have most motion, and the dorsal the 



232 FALSE VERTEBRAE. 

least. This circumstance is fully explained by the form of the 
different parts of these vertebras, and the difference in the thick- 
ness of the intervertebral substance. The necessity of fixing the 
dorsal vertebras is very evident: as their motion would greatly 
interfere with the motion of the ribs in respiration. 

The lumbar vertebras have more motion than is commonly 
supposed ; for, in addition to a certain degree of flexion, they 
perform a species of rotation or twisting, which is very observa- 
ble in persons who are diseased in one of their hip joints ; such 
persons move their whole pelvis, by a rotation of the lumbar 
vertebras, to avoid moving the diseased joint. 

— The first cause, the predisposing cause of spinal curvatures 
is the relative feebleness of the spinal column, compared to the 
forces exercised upon it, at the same time that the bones, by a 
premature increase, or by a lesion of nutrition as yet little 
known, do not acquire the degree of solidity necessary to resist 
the action of the muscles, and especially the weight of the viscera 
contained in the head, chest, &c. There results from this neces- 
sarily a curvature in one of the points of the lever, and in some 
one direction. 

— The direction of the curvature will be determined by the ine- 
quality of the forces brought into play around it. For without 
this inequality, the curvature would be direct ; that is, straight. 
It is ordinarily to the left that it has place, because the muscles 
of the right side, stronger than those of the left, draw the verte- 
bra in that direction, as Ludwig has said. — 

False Vertebra. 

The lower pyramid or under part of the spine, consists of one 
large triangular bone, called the os sacrum, and of some small 
bones, denominated the os coccygis. 

These bones are called the false vertebras, because the sacrum 
in young subjects is composed of five distinct bones, each of 
which has some resemblance to a vertebra ; but they are com- 
pletely united in the adult, and form but one bone, which is sup- 
posed to have been denominated sacrum, because it was offered 
in sacrifice by the ancients. 



OS SACRUM. 



13: 



The os sacrum is of a triangular form, with its base upwards. 
It is concave anteriorly, and convex posteriorly. The middle of 
the bone, when viewed anteriorly, appears to be composed of 
the bodies of five vertebras, united to each other, and their union 
is marked by four transverse lines. At the two extremities of 
each of these lines, are large round holes, which communicate 
with the vertebral cavity of the bone. 

On the exterior sides of these holes the surface is free from 
any marks of the original separation. 

The middle of the upper surface, or base of the bone, is 
formed for articulating with the last lumbar vertebra, and has 
two oblique processes, with a groove in each side, which forms 
part of the foramen for transmitting the twenty-fourth pair of 
nerves. 

The back part of the os sacrum is rough and convex ; in the 
middle there are commonly three processes similar to the spinous 
processes of the lumbar vertebras, and a fourth, which is much 
smaller. Below this, there is a deficiency of the bony spine, and 
the vertebral cavity is consequently open behind, but the sides of 
the canal continue lower down. 

On each side of the spinous processes are four smaller holes, 
which are opposite to the larger holes on the anterior surface. 
Between the spinous processes and the anterior part, which re- 
sembles the bodies of vertebrae, is the continuation of the vertebral 
cavity which contains the spinal marrow. From the cauda 
equina, contained in this cavity, the great nerves of the lower 
extremities pass off, through the large holes on the anterior sur- 
face, and some small nerves through the posterior holes. 

In some bones the spinous processes are entirely deficient, and 
the cavity above mentioned is completely open behind ; but the 
contained parts are defended by strong membranes. 

The anterior part of each lateral surface is covered by a plate 

of cartilage, and articulated to the os ilium. The posterior part 

is rough, and perforated by the fibres of the strong ligaments, 

which are inserted into it. 

On the posterior surface of the sacrum, the sides of the open 

vol. i. 12 



J 34 os COCCYGIS. 

part of the vertebral canal terminate, so as to form a notch 
through which passes the twenty-ninth pair of nerves. 

The os sacrum is very spongy, and is lighter in proportion to 
its bulk than any bone in the body: it is defended by the muscles 
that cover it, and the ligaments which adhere to it. 

It is articulated, above, to the last lumbar vertebra ; below, to 
the os coccygis ; and on the sides, to the ossa ilia. 

That triangular chain of bones depending from the os sacrum, 
in which each bone becomes smaller as it descends, till the last 
ends in a small tubercle, is called os coccygis. It is convex be- 
hind, and concave before; from which crooked pyramidal 
figure, which was thought to resemble a cuckoo's beak, the 
name is derived. 

There are four pieces in people of middle age. In children, 
they are almost wholly cartilaginous. In old subjects, all the 
bones are united, and become frequently one continued bone with 
the os sacrum. 

The highest of the four bones is the largest, with shoulders 
extended farther to each side than the end of the os sacrum ; 
which enlargement may serve as a distinguishing mark to fix 
the limits of either bone. The upper surface of this bone is a 
little hollow. From the back of that bulbous part called its 
shoulders, a process often rises up on each side, to join with the 
os sacrum. Sometimes these shoulders are joined to the sides of 
the open end of the vertebral canal, to form the hole in each 
side common to these two bones, for the passage of the twenty- 
ninth pair of spinal nerves. Immediately below the shoulders 
of the os coccygis, a notch may be remarked on each side, 
where the thirtieth pair of the spinal nerves passes. The lower 
end of this bone is formed into a small head, which very often is 
hollow in the middle. 

The three lower bones gradually become smaller, an-i are 
spongy, but are strengthened by a strong ligament, which covers 
and connects them. Their ends, by which they are articulated, 
are formed in the same manner as those of the first Lone. 

Between each of these four bones of young subjects a carti- 
lage is interposed ; therefore their articulation is analogous to 



VERTEBRAL CAVITY. igr 

that of the bodies of the vertebras of the neck; for the lower end 
of the os .sacrum, and of each of the three superior bones of the 
os coccygis, has a small depression in the middle; and the upper 
part of all the bones of the os coccygis is a little concave, and, 
consequently, the interpoed cartilages are thickest in the middle, 
to fill up both cavities ; by which they connect the bones more 
firmly. When the cartilages ossify, the upper end of each bone 
is formed i to a cavity, exactly adapted to the protuberant lower 
end of the bo. e immediately above. From this sort of articula- 
tion, it is evident that, unless when these bones grow together, 
all of them are capable of motion ; of which the first and second 
enjoy the largest share. 

The lower end of the fourth bone terminates in a rough point, 
to which a cartilage is appended. 

To the sides of these bones of the os coccygis, the coccygaei 
muscles, and part of the levatores ani, and of the glutaei maximi, 
are fixed. 

The connexions of these bones hinder them from being moved 
to either side ; and their motion backwards and forwards is 
much confined : yet, as their ligaments can be stretched by a 
considerable force, it is of great advantage in the excretion of 
the fasces alvinas, and much more in child-bearing, that these 
bones should remain movable ; and the right management of 
them, in delivering women, is very important. The mobility of 
the os coccygis diminishing as people advance in age, especially 
when its ligaments and cartilages have not been kept flexible by 
being stretched, is, probably, one reason why women, who are 
advanced in years before they marry, have generally difficult 
parturition. 

These bones serve to sustain the intestinum rectum ; and, 
therefore, are curved forwards ; by which they are preserved, 
as well as the muscles and teguments, from any injury when 
sitting with the body reclined back. 

The Vertebral Cavity for containing the Spinal Marrow. 
The canal, formed by the foramina of the different vertebrae, 
when these bones are placed in their natural order, extends from 



13(> THE THORAX— RIBS. 

the great occipital foramen to the end of the sacrum. Its direc- 
tion varies with the different curvatures of the spine, and its 
figure and diameter are also very different in different places. 

In the cervical vertebras, it is largest, and nearly triangular in 
form; in the dorsal, it is much smaller and almost cylindrical; 
in the lumbar, it is somewhat enlarged, and approaches again to 
the triangular figure ; in the sacrum, it is broad, but flat, and 
diminishes gradually, so as to assume the form of a long triangle. 

It has a ligamentous lining, which will be described, when an 
account is given of the fresh bones and their ligaments. 

The Thorax. 

The thorax resembles a flattened cone, cut away obliquely at 
its basis ; and regularly truncated at its apex. 

It is formed by the dorsal vertebrae behind, the ribs on the 
sides, and the sternum before. 

The Ribs 

Are long crooked bones, placed in an oblique direction down- 
wards as respects the back-bone. Their number is generally 
twelve on each side; though sometimes eleven or thirteen have 
been found. 

They are convex externally, and concave internally. They 
are made smooth by the action of the contained parts, which, on 
this account, are in no danger of being hurt by them. 

The ribs approach towards a round form at their extremities, 
near the vertebrae. Farther forwards they are flat and broad, 
and have an upper and lower edge ; each of which is made 
rough by the action of the intercostal muscles inserted into them. 
These muscles being all of nearly equal force, and equally 
stretched in the interstices of the ribs, prevent the broken ends 
of these bones, in a fracture, from being removed far out of their 
natural place, to interrupt the motion of the vital organs. The 
upper edge of the ribs is more obtuse, and rounder than the 
lower, which is deepened on its internal side by a long fossa, for 
lodging the intercostal vessels and nerves : on each side of which 
there is a ridge, to which the intercostal muscles are fixed. The 



THE RIBS j 07 

fossa is not observable at the ends of the ribs ; for, at the poste- 
rior, or root, the vessels have not yet reached the bones; and, at 
the fore end, they are split away into branches, to serve the 
parts between the ribs. 

From this situation of the blood-vessels, has originated the rule 
adopted by surgeons, that the incision, in cases of empyema, &c. 
should be made midway between the spine and sternum, and that 
the lower edge of the upper rib should be avoided. 

At the posterior end of each rib, a little head is formed, which 
is divided by a middle ridge into two flat or hollow surfaces; 
the lowest of which is generally the broadest and deepest. The 
two surfaces are joined to the bodies of two different vertebrae, 
and the ridge forces itself into the intervening cartilages. A 
little way from this head, we find, on the external surface, a 
small cavity, where mucilaginous glands are lodged ; and round 
the head, the bone appears spongy, where the capsular ligament 
of the articulation is fixed. Immediately beyond this, a flattened 
tubercle rises, with a small cavity at its root, which is surrounded 
by a roughness, for the articulation of the rib with the trans- 
verse process of the lowest of the two vertebrae, with which the 
head of the rib is joined. Advancing farther on this external 
surface, another smaller tubercle may be observed in most cases, 
into which ligaments connecting the ribs to each other, and to 
the transverse processes of the vertebrae and portions of the 
Iongissimus dorsi, are inserted. Beyond this, these bones are 
made flat by the sacro-lumbalis muscle, which is inserted into 
the part of this flat surface farthest from the spine, where each 
rib makes a considerable curve, called by some its angle. Then 
the rib begins to turn broad, and continues so to its anterior end, 
which is hollow and spongy, for the reception of, and firm coali- 
tion with, the cartilage that runs thence to be inserted into the 
sternum, or to be joined with some other cartilage. In adults, 
the cavity at this end of the ribs is generally smooth. 

The substance of the ribs is spongy, cellular, and only covered 
with a very thin external lamellated surface, which increases in 
thickness and strength as it approaches the vertebrae. 

12* 



138 THE RIBS. 

To the fore end of each rib a long, broad, and strong cartilage 
is fixed, which reaches the sternum, or is joined to the cartilage 
of the next rib. This course, however, is not in a straight line 
with the rib: for the cartilages generally make a considerable 
flexure, the concave part of which is upwards; therefore, at 
their insertion into the sternum, they make an obtuse angle 
above, and an acute one below. These cartilages are of such a 
length as never to allow the ribs to come to a right angle with 
the spine; but they keep them situated so obliquely as to make 
the angle very considerably obtuse above, till a force exceeding 
the elasticity of the cartilage is applied. These cartilages, as all 
others, are firmer and harder internally than they are on their 
external surface; and, sometimes, in old people, all their middle 
substance becomes bony, while a thin cartilaginous lamella ap- 
pears externally. The ossification, however, begins frequently 
at the external surface. The greatest alternate motions of the 
cartilages being made at their great curvature, that part remains 
frequently cartilaginous after all the rest is ossified. 

The ribs then are articulated at each end, and that behind is 
doubly joined to the vertebrae; for the head is received into the 
cavities of two bodies of the vertebra?, and a larger tubercle is 
received into the depression in the transverse process of the 
lower vertebras. When we examine the double articulation, we 
must immediately see, that no other motion can here be allowed 
than upwards and downwards. Since the transverse process 
hinders the rib to be thrusted back, the resistance of the sternum 
on the other side prevents the ribs coming forward ; and each 
of the two joints, with the other parts attached, oppose its turn- 
ing round. But then it is likewise as evident, that even the mo- 
tion upwards and downwards can be but small in any one rib at 
the articulation itself. But as the ribs advance forwards, the 
distance from their centre of motion increasing, the motion must 
be larger; and it would be very conspicuous at their anterior 
ends, were they not resisted there by the cartilages which yield 
so little, that the principal motion is performed by the middle 
part of the ribs, which turns outwards and upwards, and occa- 



THE RIBS. J39 

sions the twist remarkable in the long ribs at the place near their 
fore end where they are more resisted. 

The ribs differ from each other in the following respects : 
The upper rib is the most crooked ; and as they descend they 
become straighter. Their obliquity, with respect to the spine, 
increases as they descend, so that though their distances from 
each other are nearly equal at their back part, yet at their fore 
ends the distances between the lower ribs must increase. In 
consequence of this increased obliquity of the lower ribs, each 
of their cartilages makes a greater curve in its progress from 
the rib towards the sternum; and the tubercles that are articu- 
lated to the transverse processes of the vertebrae, have their 
smooth surfaces gradually facing more upwards. The ribs be- 
coming thus more oblique, while the sternum advances forwards 
in its descent, makes the distance between the sternum and the 
anterior end of the lower ribs greater than between the sternum 
and the ribs above ; consequently, the cartilages of those ribs that 
are joined to the breast bone are longer in the lower than in the 
higher ones. These cartilages are placed nearer to each other 
as the ribs descend, which occasions their curvature to be 
greater. 

The length of their ribs increases from the first and upper- 
most rib, as far down as the seventh ; and from that to the 
twelfth, it gradually diminishes. The superior of the two sur- 
faces, by which the ribs are articulated to the bodies of the ver- 
tebras, gradually increases from the first to the fourth rib, and 
is diminished after that in each lower rib. The distance of 
their angles from the heads always increases as they descend 
to the ninth, because of the greater breadth of the sacro-lumbalis 
muscle. 

The ribs are commonly divided into true and false. 
The true ribs are the seven uppermost of each side. Their 
cartilages are all gradually longer as they descend, and are 
joined to the breast bone: so that, being pressed constantly be- 
tween two bones, they are flattened at both ends ; and are 
thicker, harder, and more liable to ossify than the other carti- 



140 



THE RIBS. 



lages that are not subject to so much pressure. These bones 
include the heart and lungs; and therefore are called true ribs. 

The five inferior ribs of each side are the false, whose car- 
tilages do not reach to the sternum ; but on this account having 
less pressure, their substance is softer. To these five ribs the 
circular edge of the diaphragm is connected. 

The first rib of each side is so situated, that the flat sides are 
above and below, while one edge is placed inwards, and the 
other outwards, or nearly so ; therefore sufficient space is left 
above it for the subclavian vessels and muscles ; and the broad 
concave surface is opposed to the lungs. But in consequence of 
this situation, the channel for the intercostal vessels is not to be 
found. The head of this rib is not divided into two plane sur- 
faces by a middle ridge, because it is only articulated with the 
first vertebra of the thorax. Its cartilage is frequently ossified 
in adults, and is united to the sternum at right angles. This first 
rib frequently has a ridge rising near the middle of its posterior 
edge, where one of the heads of the scalenii muscles rises. 
Farther forward it is flattened, or sometimes depressed by the 
clavicle. 

The position of the second rib is such that its two broad sur- 
faces have oblique aspects, inward and downwards, outwards, 
and upwards, so as to make the surface of the thorax uniform : 
and it may be observed of all the ribs, that the aspect of their 
surfaces is varied upon this principle, according to their situation 
in the thorax. 

The sixth, seventh, and eighth ribs have their cartilages nearly 
contiguous. They are frequently joined to each other by cross 
cartilages ; and frequently the cartilages of the eighth, ninth, 
and tenth, are connected to the former, and to each other by firm 
ligaments. 

The eleventh, and sometimes the tenth rib, has no tubercle 
for its articulation with the transverse process of the vertebra, 
to which it is only loosely fixed by ligaments. The fossa, in its 
lower edge, is not so deep as in the upper ribs; because the ves- 
sels run more towards the interstice between the ribs. Its front 



THE STERNUM. 



141 



end is smaller than its body; and its short small cartilage is but 
loosely connected to the cartilage of the rib above. 

The twelfth rib is the shortest and straightest. Its head is only 
articulated with the last vertebra of the thorax ; and therefore 
is not divided into two surfaces. This rib is not joined to the 
transverse process of the vertebra, and therefore has no tubercle, 
being often pulled necessarily inwards by the diaphragm, which 
an articulation with the transverse process would not have 
allowed. The fossa is not found at its upper edge, because the 
vessels run below it. The forepart of this rib is smaller than its 
middle, and has only a very small pointed cartilage fixed to it. 
To its whole internal side the diaphragm is connected. 

The Sternum 

Is the broad flat bone, in the front part of the thorax. In 
adults it is composed of three pieces, which easily separate 
after the cartilages connecting them are destroyed. The two 
lower pieces are frequently found intimately united ; and very 
often, in old people, the sternum is a continued bony substance 
from one end to the other ; though we still observe two, some- 
times three, transverse lines on its surface; which are marks 
of the former divisions. 

The sternum, considered as one bone, is broadest and thickest 
above, and smaller as it descends. The internal surface of this 
bone is somewhat concave for enlarging the thorax : but the 
convexity on the external surface is not so conspicuous, because 
the sides are pressed outwards by the true ribs ; the round 
heads of whose cartilages are received into seven smooth pits, 
formed in each side of the sternum, and are kept firm there by 
strong ligaments, which, on the external surface, have a parti- 
cular radiated texture. The pits, at the upper part of the 
sternum, are at the greatest distance one from another, and as 
they descend, are nearer; so that the two lowest are contiguous. 

The substance of the breast bone is cellular, with a very thin 
external plate, especially on its internal surface, where we may 
frequently observe a cartilaginous crust spread over it. On both 



142 THE STERNUM. 

surfaces, however, a strong ligamentous membrane is closely 
braced ; and the cells of this bone are so small, that a consider- 
able quantity of osseous fibres must be employed in the com- 
position of it. Whence, with the defence which the muscles 
give it, and the movable support it has from the cartilages, it is 
sufficiently secured from being broken : for it is strong by its 
quantity of bone; its parts are kept together by ligaments; and 
it yields enough to elude considerably any violence offered. 

The three pieces which compose this bone are very different 
from each other. 

The first piece resembles a triangle, with the corners cut off. 
The upper edge of it is thick, and has a regular depression in 
the middle, to accommodate the trachea. On each side of this 
depression is a superficial cavity, which, on viewing it trans- 
versely, from before backwards, appears a little convex. Into 
these cavities the ends of the clavicles are received. Imme- 
diately below them, the sides of this bone become thinner ; and 
in each a superficial cavity, or a rough surface is to be seen, 
where the first ribs are received or joined to the sternum. In 
the side of the under end of this first bone, the half of the pit 
for the second rib on each side is formed. The upper part of 
the surface behind is covered with a strong ligament, which 
secures the clavicles ; and is afterwards to be more particularly 
taken notice of. 

The second, or middle division of this bone, is much longer, 
narrower, and thinner, than the first ; but, excepting that it is a 
little narrower above than below, it is nearly uniform in its 
dimensions of breadth or thickness. In the sides of it are com- 
plete pits for the third, fourth, fifth, and sixth ribs, and one half 
of the pits for the second and seventh ; the lines, which are 
marks of the former division of this bone, being extended from 
the middle of the pits of one side, to the middle of the corre- 
sponding pits of the other side. Near its middle an unossified 
part of the bone has sometimes been found ; which, freed of the 
ligamentous membrane or cartilage that fills it, is described as a 
hole. When the cartilage between this and the first bone is not 



THE STERNUM. 



143 



ossified, a manifest motion of this upon the first may be observed 
in respiration ; or in raising the sternum, by pulling the ribs up- 
wards; or distending the lungs with air, in a recent subject. 

The third bone is much less than the other two, and has only 
one half of the pit for the seventh rib formed in it; wherefore 
it might be reckoned only an appendix of the sternum. In young 
subjects it is always cartilaginous, and is better known by the 
name of cartilago-xiiphoid.es or ensiformis, than any other. This 
third bone is seldom of the same figure, magnitude, or situation, 
in any two subjects; for, sometimes, it is triangular; with one 
of the angles below, and perpendicular to the middle of the 
upper side, by which it is connected to the second bone. In 
other persons, the point is turned to one side ; or obliquely for- 
wards or backwards. Frequently it is nearly of an equal breadth, 
and often it is bifurcated ; sometimes, also, it is unossified in the 
middle. In the greatest number of adults, it is ossified, and 
tipped with a cartilage ; in some, one half of it is cartilaginous; 
and in others, it is all in a cartilaginous state. 

The sternum is joined by cartilages to the seven upper ribs, 
except when the first coalesce with it. It is also articulated with 
the clavicles. 

It contributes to the formation of the cavity of the thorax, and 
supports the mediastinum. As a movable fulcrum for the ribs, 
it assists in respiration ; and it affords origin and insertion to 
several muscles. 

The movement of the Ribs and Sternum in inspiration. 

The ribs and their cartilages are articulated to the spine behind, 
and the sternum before, in a way which admits of a compound 
motion. 

They are drawn from a position which slopes obliquely down- 
wards and forwards, into one which is more horizontal ; and the 
posterior extremity of each rib, which is the centre of this motion, 
is moved very little, while the anterior extremity moves much 
more. 

At the same time, the ribs perform a rotation outwards, upon 
their extremities connected with the spine and sternum ; in con- 



144 THE PELVIS. 

sequence of which, the middle of each rib is moved outwards to 
a considerable extent. 

It is very obvious, that, by these motions, the thorax must be 
enlarged from side to side, and from behind forwards. 

As the ribs are raised from the oblique towards the horizontal 
position, the sternum is necessarily moved forward by them ; and, 
if this bone does not move upon the first rib, the rib must move 
to accommodate it : a small motion at the articulation of the rib 
with the spine, being sufficient to produce considerable motion at 
the lower end of the sternum. The sternum, therefore, vibrates 
forward when the ribs are elevated, and backward when they 
are depressed. 

In easy respiration, these motions are not very great, for then 
the enlargement of the thorax appears to be produced by the in- 
crease of its vertical diameter, in consequence of the descent of 
the diaphragm; but when the inspirations are very large, and 
when the descent of the diaphragm is impeded, as in preg- 
nancy, and in ascites, these motions are very considerable* 

It ought to be observed, that the first rib has very little motion, 
except the rotation which favours the motion of the sternum ; and 
that the lower ribs, having no support at their anterior extremities, 
have no rotation. 

The Pelvis. 

The pelvis is the cavity at the lower part of the trunk, formed 
by the os sacrum, os coccygis, and ossa innominala. 

The ossa innominata are the two large bones which are con- 
nected to the sacrum behind, and to each other by the interven- 
tion of a cartilage in front. 

Each of the ossa innominata is composed of three portions, 
in children ; and although these are united in adults, so as to 
form but one bone, yet anatomists have generally considered the 
bone as divided into its original parts, which are denominated os 
ilium, os ischium, and os pubis. 

The original separation is at the acetabulum, or cavity for re- 
ceiving the head of the os femoris, which is on the outside of 
the os innominatum. The upper and posterior part of this cavity, 



OS ILIUM. j 45 

to the amount of two-fifths, is formed by the os ilium, two-fifths 
of the inferior portion by the os ischium, and the anterior fifth 
by the os pubis. 

The Os Ilium 

Is the largest of the three portions. Its external surface has 
been called its dorsum, and the internal concave surface its 
costa or venter. The semicircular edge at the upper part of the 
bone, is named the spine ; the external oblique muscle of the ab- 
domen is inserted into it, and the internal oblique, and the trans- 
versalis arise from it. The ends of the spine are prominent, 
and therefore are called processes. At a small distance below 
the anterior spinous process, is another protuberance, called the 
inferior anterior spinous process ; and the edge of the bone be- 
tween these two processes is curved. 

Below the posterior spinal process, another protuberance is 
also observable, which is applied closely to the os sacrum. 
Under this is a large notch, which, with the ligaments that pass 
from the os sacrum to the os ischium, forms a foramen, through 
which the great sciatic nerve, the pyriform muscle, and some 
blood-vessels pass. 

The external surface, or dorsum, of the os ilium, is greatly 
undulated by the action of muscles that lie upon it ; the gluteus 
maximus, on the posterior, and the gluteus medius and minimus, 
on the anterior parts of it. The lower part of this bone, which 
contributes to the formation of the acetabulum, is the thickest. 

The internal surface of the os ilium is concave, and supports 
some of the intestines. From this concave surface a slight con- 
cavity is continued obliquely forwards, at the inside of the ante- 
rior inferior spinal process, where part of the psoas and iliacus 
muscles, with the crural vessels and nerves pass. The large 
concavity is bounded below by a sharp ridge, which runs from 
behind forwards; and, being continued with such another ridge 
of the os pubis, forms a line of partition between the cavities of 
the abdomen and pelvis. Into this ridge the broad tendon of the 
psoas parvus is inserted. 

All the internal surface of the os ilium, behind the continu- 

VOL. I. 13 



146 0S ISCHIUiM. 

ance of this ridge, is very unequal : for the upper part is fiat, 
but spongy, where the sacro-lumbalis and longissimus dorsi rise. 
Lower down, there is a transverse ridge from which ligaments 
go out to the os sacrum. Immediately below this ridge, the 
rough unequal cavities and prominences are placed, which are 
exactly adapted to those described on the side of the os sacrum. 
In the same manner, the upper part of this rough surface is po- 
rous, for the firmer adhesion of the ligamentous cellular sub- 
stance ; while the lower part is more solid, and covered with a 
thin cartilaginous skin, for its immovable articulation with the 
os sacrum. From all the circumference of this large unequal 
surface, ligaments are extended to the os sacrum, to secure more 
firmly the conjunction of these bones. 

The passages of the medullary vessels are very conspicuous, 
both in the dorsum and costa of many ossa ilia ; but in others 
they are inconsiderable. 

The posterior and lower parts of these bones are thick ; but 
they are generally exceedingly thin and compact at their middle, 
where they are exposed to the actions of the musculi glutaei and 
iliacus internus, and to the pressure of the bowels contained in 
the belly. The substance of the ossa ilia is cellular, except a 
thin external plate. 

The Os Ischium, 

Or hip-bone, is of a middle size, between the two other parts 
of the os innominatum, and of a very irregular figure. Its 
extent might be marked by a horizontal line drawn a little 
below the middle of the acetabulum; for the upper bulbous part 
of this bone forms rather less than the lower half of that great 
cavity, and the small leg of it rises to much the same height, on 
the other side of the great hole, common to this bone and the 
os pubis. 

From the upper thick part of the os ischium, a sharp process, 
called by some authors spinous, stands out backwards, from 
which chiefly the musculus coccygaeus and superior gemellus, 
and part of the levator ani, rise; and the anterior, or internal, 
sacro-sciatic ligament is fixed to it. Between the upper part of 
this ligament and the bones, '" c ' ' ' **,-» **-- 



os pubis. j 47 

pyriform muscle, the posterior crural vessels, and the sciatic 
nerve, pass out of the pelvis. Immediately below this process, 
is a depression for the tendon of the obturator internus muscle. 
In a recent subject, this part of the bone serves as a pulley on 
which the obturator muscle plays with a ligamentous cartilage. 

Below the depression of the obturator muscle, is the great 
knob or tuberosity, covered with cartilage or tendon. The up- 
per part of the tuberosity gives rise to the inferior gemellus 
muscle. To a ridge at the inside of this, the external, or poste- 
rior sacro-sciatic ligament is so fixed, that between it, the inter- 
nal ligament, and the sinuosity of the os ischium, a passage is 
left for the internal obturator muscle. The upper thick smooth 
part of the tuber, called by some its dorsum, has two oblique im- 
pressions on it. The inner one gives origin to the long head of 
the biceps flexor cruris, and semilendinosus muscles ; and the 
semimembranosus rises from the exterior one, which reaches 
higher and nearer the acetabulum than the other. The lower, 
thinner, more scabrous part of the knob, which bends forwards, 
is also marked with two flat surfaces ; whereof the internal is 
what we lean upon in sitting, and the external gives rise to the 
largest head of the triceps adductor femoris. Between the ex- 
ternal margin of the tuberosity, and the great hole of the os in- 
nominatum, there is frequently an obtuse ridge extended down 
from the acetabulum, which gives origin to the quadratus femoris. 
As the tuber advances forwards, it becomes smaller, and is 
rough for the origin of the musculus transversalis and erector 
penis. The small leg of it, which mounts upwards to join the 
os pubis, is rough and prominent at its edge, where the two lower 
heads of the triceps adductor femoris take their rise. 

The upper and back part of the os ischium is broad and thick ; 
but its lower and forepart is narrower and thinner. Its sub- 
stance is of the structure common to broad bones. 

The os ilium and pubis, of the same sides, are the only bones 
which are contiguous to the os ischium. 

The Os Pubis, 

The least of the three portions of the os innominatum, is 
placed at the upper and front part of it. The thick, largest 



j 48 os pubis. 

part of this bone is employed in forming the acetabulum ; from 
which, becoming much smaller, it is stretched inwards to its 
fellow of the other side, where it again grows larger, and 
forms a surface to be connected with the cartilage of its sym- 
physis and then sends a small branch downwards to join the end 
of the small leg of the os ischium. The upper surface of each 
os pubis is broad, near its junction with the cartilage of the sym- 
physis ; on the internal edge of this surface begins a ridge, which 
is continued from it along the os ilium, and forms the division be- 
tween the cavities of the abdomen and pelvis. This ridge is 
called crista, and includes that on the ilium, linea innominata, or 
ileo-pectinea. On the anterior and external edge of this surface 
of the pubis, at a small distance from the cartilage, is a promi- 
nence or process, called the spine. From this process, another 
ridge, which is much more obtuse, extends to the acetabulum. 
The upper surface of the pubis, which is included between these 
ridges, is concave, for the transmission of the crural vessels, and 
nerve, and the psoas and iliacus internus muscles. 

Immediately below the lower ridge, and near the acetabulum, 
a winding notch is made, which is comprehended in the great 
contiguous foramen ; but is formed into a hole in the recent sub- 
ject by a subtended ligament, for the passage of the posterior 
crural nerve, and artery, and vein. The internal end of the os 
pubis is rough and unequal, for the firmer adhesion of the thick 
ligamentous cartilage that connects it to its fellow of the other 
side. The process which goes down from that to the os ischium 
is broad and rough before, where the gracilis and upper heads 
of the triceps adductor femoris have their origin. 

The substance of the os pubis is the same as that of other 
broad bones. 

Between the os ischium and pubis a very large irregular hole 
is left, which has been called thyroideum. The whole of this 
foramen, except the notch for the posterior crural nerve, is 
filled up, in a recent subject, with a strong ligamentous mem- 
brane, that adheres very firmly to its circumference. From this 
membrane chiefly, the two external and internal obturator mus- 
cles take their rise. The great design of this hole, besides ren- 
dering the bone lighter, is, to ~"~— - ■ • 



ACETABULUM. 1 49 

rator muscles, and sufficient space for lodging them ; that there 
may be no danger of disturbing the functions of the contained 
viscera of the pelvis by the actions of the internal ; nor of the 
external being bruised by the thigh bone, especially by its lesser 
trochanter, in the motions of the thigh inwards : both which in- 
conveniences must have happened, had the ossa innominata been 
complete here, and of sufficient thickness and strength, as the 
fixed point of these muscles. 

The bowels sometimes make their way through the notch for 
the vessels at the upper part of this thyroid hole; and this causes 
a hernia in this place. 

The acetabulum is situated near the outside of the great fora- 
men. The margin of this cavity is very high, and is still much 
more enlarged by the ligamentous cartilage, with which it is 
tipped in a recent subject ; round the base of this margin the 
bone is rough and unequal, where the capsular ligament of the 
articulation is fixed. At the upper and back part of the aceta- 
bulum the margin is much larger and higher than any where 
else ; which is very necessary to prevent the head of the femur 
from slipping out of its cavity at this place, where the whole 
weight of the body bears upon it, and consequently might other- 
wise thrust it out. As the margin is extended downwards and 
forwards, it becomes less; and, at the internal lower part, is a 
deficiency in it; from the one side of which to the other, a liga- 
ment is placed in the recent subject, under which a large hole is 
left. Besides this difference in the height of the margin, the 
acetabulum is otherwise unequal; for the lower internal part of 
it is depressed below the cartilaginous surface of the upper part, 
and is not covered with cartilage ; into the upper part of this 
particular depression, where it is deepest, and of a semilunar 
form, the ligament of the thigh bone, commonly, though impro- 
perly called the round one, is inserted: while, in its more super- 
ficial lower part, a mass of adipose matter is lodged. The great- 
est part of this separate depression is formed in the os ischium. 

The ossa innominata are joined, at their back part, to each 
side of the os sacrum, by a sort of suture, with a very thin inter- 
vening cartilage, which serves to cement these bones together: 

13 * 



J 50 CAVITY OF THE PELVIS. 

and strong ligaments go from the circumference of this unequal 
surface to connect them more firmly. They are connected to- 
gether at their forepart by the ligamentous cartilage interposed 
between the two ossa pubis, and therefore have no motion in a 
natural state, except what is common to the trunk of the body, 
or to the os sacrum. 

Considering the great weight that is supported in our erect 
posture, by the articulation of the ossa innominata with the os 
sacrum, there is great reason to think, that, if the conglutinated 
surfaces of these bones were once separated, (without which 
the ossa pubis cannot move on each other,) the ligaments would 
be violently stretched, if not torn. 

Each os innominatum affords a socket (the acetabulum) for 
the thigh bones to move in ; and the trunk of the body rolls so 
much on the heads of the thigh bones as to allow here the most 
conspicuous motions of the trunk, which are commonly thought 
to be performed by the bones of the spine. 

The form of the cavity of the pelvis, at its upper opening, or 
brim, is somewhat oval; as a line drawn from one side to the 
other, is about an inch longer than a line drawn from the back 
to the front part of it. 

This margin is well denned by the ridge on the surface of the 
ossa ilia, and the upper edge of the os pubis ; but the margin of 
the lower opening is very irregular; and it ought to be observed, 
that the dimensions of this opening are made less by the sacro- 
sciatic ligaments, than they appear upon an examination of the 
bare bones. 

In consequence of the oblique position of ihe sacrum, sloping 
downwards and backwards, the position of the pelvis is very 
oblique. A line drawn through the centre of this cavity, per- 
pendicular to the plane of the upper orifice, or brim, would not 
coincide with the vertical diameter of the cavity of the abdo- 
men, but would pass out of that cavity near the umbilicus. 

This cavity, and the bones which form it, are different in the 
two sexes. 

In women, the brim of the pelvis is wider, and inclines more 
to the oval form. 

In men this opening is mo: 



CAVITY OF THE PELVIS. 



151 



The outlet or lower opening of the pelvis is also larger in 
women. 

This greater size of the pelvis and its openings, in women, is 
derived particularly from the following circumstances : 

The os sacrum is broader, and sometimes straighter than in 
men. 

The ossa ilia are flatter, and consequently the ossa ischia are 
farther apart. 

The ligamentous cartilage at the symphysis pubis is broader, 
and shorter. 

The angle formed by the crura of the ossa pubis with each 
other, at the symphysis, is much larger. 

— The pelvis, considered as a whole, is very irregular, though 
symmetrical in its shape. It has the form of a truncated cone, 
or a funnel with its base upwards, curved from behind forward 
with its concavity in front, and is bounded both above and be- 
low by bony walls of unequal elevation. It is divided by the 
projection of the base of the sacrum and the two ilio-pectineal 
lines, into a greater and lesser pelvis, the former of which is 
above. The dividing line is called the superior strait of the 
lesser pelvis. The bony walls of the greater pelvis is incom- 
plete. The boundaries of this cavity, are formed upon the sides 
by the iliac fossas, and behind by a notch which is nearly filled 
up, when the last lumbar vertebrae is left connected with the sa- 
crum,* and in front all the wide triangular opening between the 
anterior superior spine of the ilium of each side and the sym- 
physis pubis is filled up by the lower part of the abdominal 
muscles. From the flaring direction of the upper part of the 
ilia, the diameters of the base of this cavity, or that towards the 
abdomen, is greater than those opposite the ilio-pectineal lines. 
— The lesser pelvis, forms nearly an entire bony canal, and 
which the student is too apt to consider as constituting the whole 
pelvis. This cavity is larger at its middle than at its extremities. 
It is bounded behind by the sacrum and coccyx ; in front by the 
symphysis pubis and a part of the obturator foramen ; and upon 
the sides, by the bony surface which corresponds to the cotyloid 

* The attachment of the lumbar muscles completes this wall behind. 



152 DIMENSIONS OP THE PELVIS. 

cavity. Its superior margin (superior strait,) is regular and 
ovoidal in its shape. Its longest diameter is transverse. Its in- 
ferior strait is very irregular, though symmetrical in the form of 
its bony walls ; and in consequence of the posterior walls of this 
pelvis being of much greater length than the anterior, presents 
an oblique cut, which presents slightly forwards, so that if its 
axis was extended downwards, it would cross just above the 
middle of the thigh. It is bounded behind, by the point of the 
coccyx; in front, by the symphysis pubis; and on the side, by 
the tuberosities of the ischium. The sacro-sciatic notches and 
the arch of the pubis, filled up by ligaments and soft parts. 
From the general form of the whole pelvic cavity it will then be 
obvious, that a body passing through its axis from above down- 
wards, must advance successively in three directions: 1st, as it 
passes through the greater pelvis, obliquely backicards; 2d, ver- 
tically; and 3d, as it passes through the inferior strait, obliquely 
forwards. 

— For obstetrical purposes, it is necessary for the student to 
have precise notions in regard to the dimensions of the pelvis. 
To determine this, it is necessary to measure the superior open- 
ing of the greater pelvis, and the two straits of the lesser. 
— The pelvis of the male, diners in many respects from that of 
the female. In the former length predominates, in the latter, 
breadth. In the female all the diameters of the pelvis are more 
extensive than those of the male, which is caused by the greater 
size and outward direction of the iliac fossae, and from a less 
degree of curvature in the iliac crests, from the roundness of the 
pubic arch which in the male forms an acute angle. In con- 
sequence of the wider space which exists between the cotyloid 
cavities, the gait of the female is characterised by more lateral 
rotation or waddling, than that of man. 

— In a well formed woman, the different measurements are 
nearly as follows : 

Greater Pelvis. 

— In the superior opening of the greater pelvis, we distinguish 
but two diameters, both transverse. The posterior extended from 
the middle of one iliac crest - " " 



DIMENSIONS OF THE PELVIS. 



153 



anterior, between the two anterior superior spinous processes of 
the ilium, ten inches. From the middle of the iliac crest, to the 
superior strait, three and a half inches. From the middle of 
the iliac crest to the tuberosity of the ischium, (whole depth of 
the pelvis) seven and a half inches nearly.* 

Lesser Pelvis. 

Superior Strait, sometimes called ab- Inferior Strait, or perineal, 

dominal. 

Inches. Inches. 

Antero posterior diameter, from Antero-posterior diameter, be- 

the symphysis of the pubis to tween the symphysis pubis and 

the promontory of the sacrum, 4 front of the coccyx, which may 
7'ransverse, or iliac, which be increased near an inch by 

crosses the former, at a right an- the mobility of the coccyx 

gle, -...- 5 backwards, ... 4 

Oblique, from the acetabulum Transverse, or ischiatic, from 

of one side, to the sacro-iliac ar- one tuberosity of the ischium to 

ticulation of the other, - 4J the other, .... 4 

Oblique, from the tuberosity 
of the ischium of one side, to the 
middle of the great sacro-sciatic 
ligament of the other, nearly 4 

The height of the posterior wall of the lesser pelvis, 
formed by the sacrum and coccyx, (of which the 

latter forms an inch,) is nearly - - - - 5 inches. 

Height of the anterior wall formed by the os pubis, - 1£ " 

Height of the lateral walls, 3£ " 

Thickness of the symphysis pubis, about - - - $ " 

Depth or sine of the cavity of the sacrum,f nearly - 1 " 

The Trunk of the Foztus. 

At birth, each vertebra consists of three pieces, connected by 

cartilages, viz.: The body, not perfectly ossified; and a bone on 

each side of it, of a form almost rectangular, on which the oblique 

processes are very distinguishable, and the transverse processes 

* The depth or length of the pelvis is rather greater in the male than in the 
female. 

t Dimensions of the child's head at birth. The long diameter, from the vertex 
or posterior extremity of the sagittal suture to the chin, 5^ inches; antero-pos- 
terior, from the middle of the frontal bone to the tubercle of the occipital, 4 
inches; transverse, from one parietal protuberance to the other, 3J inches. 



j 54 0F THE SUPERIOR EXTREMITIES. 

may be ascertained. These bones are so applied to the body, 
as to include a triangular space for the vertebral cavity. The 
ends of the longest portions are nearly in contact behind ; but 
the spinous process is not formed. The atlas is cartilaginous in 
front, and has only the two lateral portions ossified. The vertebra 
dentata consists of four pieces ; for, in addition to the three pieces 
common to the other vertebras, the processus dentatus is a dis- 
tinct portion. 

The false vertebra, of which the sacrum consists, are each 
formed of three bones as the true vertebras. 

The bones of the os coccygis are cartilaginous, except the first, 
which is partly ossified. 

The ribs are almost perfect at birth: their heads and tuber- 
cles covered with cartilage. The necessity of their motion in 
respiration, immediately after birth, explains this difference be- 
tween them, and most of the other bones of the foetus. 

The sternum consists of several small bones, surrounded by 
flat cartilages. Ossification goes on in these cartilages from 
various points; and the distinct bones finally unite into the three 
pieces of which the sternum is finally composed. 

The ossa innominata, on each side, are formed of three dis- 
tinct pieces, united at the acetabulum. 

The spine of the os ilium is cartilaginous ; and the lower part 
of the bone is not completely ossified. 

The back part of the os ischium is ossified ; but the portion 
which forms the acetabulum, the tuber, and the crus, is carti- 
laginous. 

The upper part of the os pubis, and that portion which forms 
the symphysis, are ossified. The crus, like that of the ischium, 
is cartilaginous. 

Of the Superior Extremities. 

Each superior extremity consists of the Shoulder, the Arm, 
the Forearm, and the Hand. 

The shoulder is composed of the clavicle and scapula. It has 
been supposed by some persons that the two last mentioned 
bones belong properly to the thorax; but upon examining the 
motions of the upper extremil :.:.. '". 



THE CLAVICLE. jtc 

essential part of it: and it is equally evident that they do not 
contribute to the perfection of the thorax ; they are, therefore, 
considered as a part of the upper extremity. 

The Clavicle, 

Is the long crooked bone resembling the italic f, which is 
placed almost horizontally between the upper lateral part of the 
sternum and the acromion, or most prominent process of the 
scapula which it keeps off from the trunk of the body. 

The clavicle, as well as other long bones, is larger at its 
two ends than in the middle. The end next to the sternum is 
triangular; the angle behind is considerably protruded, to form 
a sharp ridge, to which the transverse ligament, extended from 
one clavicle to the other, is fixed. The side opposite to this is 
somewhat rounded. The middle of this protuberant end is 
irregularly hollowed, as well as the cavity in the sternum for 
receiving it: but, in a recent subject, the irregular concavities 
of both are supplied by a movable cartilage; which is not only 
much more closely connected every where, by ligaments, to the 
circumference of the articulation, than those of the lower jaw 
are, but it grows to the two bones at both its internal and ex- 
ternal end ; its substance at the external end being soft, but very 
strong, and resembling the intervertebral cartilages. 

From its internal end, the clavicle, for about two-fifths of its 
length is bended obliquely forwards. On the upper and front 
part of this curvature a small ridge is seen, with a plane rough 
surface before it; whence the sterno-hyoidcus and sterno-mas- 
toideus muscles have in part their origin. Near the lower angle, 
a small plane surface is often to be remarked, where the first rib 
and this bone are contiguous, and are connected by a firm liga- 
ment. From this a rough plane surface is extended outwards, 
where the pectoral muscle has part of its origin. Behind, the 
bone is made flat and rough by the insertion of the larger 
share of the subclavian muscle. The clavicle is then curved 
backwards, and at first is round; but it soon after becomes 
broad and thin ; which shape it retains to its external end. 
Along the external concavity a rough sinuosity runs; from 
which some part of the deltoid muscle takes its rise : opposite to 



156 THE CLAVICLE. 

this, on the convex edge, a scabrous ridge gives insertion to a 
share of the trapezius muscle. The upper surface of the clavi- 
cle is here flat; but the lower is hollow, for lodging the begin- 
ning of the musculus subclavius; and towards its back part a 
tubercle rises ; to which, and to a roughness near it, the strong, 
short, thick, ligament, connecting this bone to the coracoid pro- 
cess of the scapula, is fixed. 

The external end of this bone is oblong horizontally, smooth, 
sloping at the posterior side, and tipped in a recent subject with 
a cartilage, for its articulation with the acromion scapulas. 
Round this the bone is spongy, for the firmer connexion of the 
ligaments. 

The surfaces of contact with this bone, and the scapula are 
remarkably small, and flat also. 

The medullary arteries, having their direction obliquely out- 
wards, enter the clavicles by one or more small passages in the 
middle of their back part. 

The substance of this bone is the same as that of the other 
round long bones. 

The ligaments which surround the articulation of this bone 
with the sternum, are so short and strong, that little motion can 
be allowed any way ; and the strong ligament that is stretched 
across the upper furcula of the sternum, from the posterior pro- 
minent angle of the one clavicle to the same place of the other 
clavicle, serves to keep each of these bones more firmly in its 
place. By the assistance, however, of the movable intervening 
cartilage, the clavicle can move at this articulation, so that the 
external extremity may be elevated or depressed, and moved 
backwards and forwards. The whole bone may be moved so 
as to describe a cone; of which the end at the sternum is the 
apex. 

The movements of the scapula and arm are the objects of 
these motions of the clavicle ; and the general use of the bone is 
to regulate the motions of these parts. 

From the situation, figure, and use of the clavicles, it is evi- 
dent that they are much exposed to fractures; thai their broken 
parts must generally pass each other, and that they will be kept 
in their places with difficulty- 



THE SCAPULA. 



157 



The Scapula, 

Or shoulder-blade, is the triangular bone situated on the upper 
and back part of the thorax. The back part of the scapula has 
nothing but the thin ends of the serratus anticus major, and sub- 
scapulars muscles between it and the ribs : but as this bone ad- 
vances forwards, its distance from the ribs increases. The 
longest side of this bone is nearest the spine, and has an oblique 
position as respects it. The upper or shortest side, called the 
superior costa of the scapula, is nearly horizontal, and parallel 
with the second rib. The lower side, which is named the in- 
ferior costa, is extended obliquely from the third to the eighth 
rib. The situation of this bone, here described, is, when people 
are sitting or standing, in a state of inactivity, and allowing the 
members to remain in the most natural easy posture. The in- 
ferior angle of the scapula is very acute ; the upper one is near 
to a right angle ; and what is called the anterior does not de- 
serve the name, for the two sides do not meet to form an angle. 
The body of this bone is concave towards the ribs, and convex 
behind, where it has the name of dorsum. Three processes are 
generally reckoned to proceed from the scapula. The first is 
the large spine that rises from its convex surface behind, and 
divides it unequally. The second process stands out from the 
forepart of the upper side ; and, from its imaginary resemblance 
to a crow's beak, is named coracoides. The third process is the 
whole thick bulbous forepart of the bone. 

Into the oblique space the musculus patientiae {levator scapulce) 
is inserted. At the root of the spine, on the back part of the 
base, a triangular fiat surface is formed by the pressure of the 
lower fibres of the trapezius. Below this, the edge of the 
scapula is scabrous and rough, for the insertion of the serratus 
major anticus and rhomboid muscles. 

The back part of the inferior angle is made smooth by the 
latissimus dorsi passing over it. This muscle also alters the 
direction of the inferior costa some way forwards from this 
angle : and so far it is flattened behind by the origin of the teres 
major. As the inferior costa advances forward, it is of con- 

vol. i. 14 



158 THE 3CAPULA. 

siderable thickness, is slightly hollowed, and made smooth be- 
hind, by the teres minor; while it has a fossa formed into it be- 
low, by part of the subscapulars ; and between the two, a ridge 
with a small depression appears, where the longus extensor 
cubiti has its origin. 

The superior costa is very thin ; and near its forepart there is 
a semilunar notch, from one end of which to the other, a liga- 
ment is stretched ; and sometimes the bone is continued to form 
one, or sometimes two holes, for the passage of the scapula, 
blood-vessels and nerves. Immediately behind this semilunar 
cavity, the coraco-hyoideus muscle has its rise. From the notch, 
to the termination of the fossa for the teres minor, the scapula is 
narrower than any where else, and supports the third process. 
This part has the name of cervix. 

The whole dorsum of the scapula is always said to be convex; 
but, by reason of the raised edges that surround it, it is divided 
into two cavities by the spine, which is stretched from behind 
forwards, much nearer to the superior than to the inferior costa. 
The cavity above the spine is really concave, where the supra- 
spinal muscle is lodged ; while the surface of this bone below 
the spine, on which the infra-spinatus muscle is placed, is convex, 
except a fossa that runs at the side of the inferior costa. 

The internal or anterior surface of this bone is hollow, except 
in the part above the spine, which is convex. The subscapulars 
muscle is extended over this surface, where it forms several 
ridges and intermediate depressions, commonly mistaken for 
prints of the ribs : they point out the interstices of the bundles 
of fibres of which the subscapulars muscle is composed. 

The spine rises small at the base of the scapula, and becomes 
higher and broader as it advances forwards. On the sides it is 
unequally hollowed and crooked, by the action of the adjacent 
muscles. Its ridge is divided into two rough, flat surfaces: into 
the upper one the trapezius muscle is inserted; and the lower 
one has part of the deltoid fixed to it. The end of the spine, 
called acromion, or top of the shoulder, is broad and flat, and is, 
sometimes, only joined to the spine by a cartilage. The anterior 
edge of the acromion is flat, smooth, and covered with a carti- 



THE SCAPULA. . cq 

lage, for its articulation with the external end of the clavicle ; 
and it is hollowed below, to allow a passage to the infra and 
supra-spinati muscles, and free motion to the os humeri. 

The coracoid process is crooked, with its point inclining for- 
wards; so that a hollow is left at the lower side of its root for 
the passage of the subscapulars muscle. The end of this pro- 
cess is marked with three plane surfaces. Into the internal, the 
pectoralis is inserted ; from the external, one head of the biceps 
flexor cubiti rises ; and from the lower one, the coraco-brachialis 
has its origin. At the upper part of the root of this process, 
immediately before the semilunar cavity, a smooth tubercle ap- 
pears, where a ligament from the clavicle is fixed. From the 
whole of the external side of this coracoid apophysis a broad 
ligament goes out, which becomes narrower where it is fixed to 
the acromion. 

From the cervix scapulas the third process is produced. The 
forepart of this is formed into a glenoid cavity, which is of the 
shape of the longitudinal section of an egg, being broad below 
and narrow above. Between the margin of this cavity and the 
forepart of the root of the spine, a large sinuosity is left for the 
transmission of the supra and infra-spinati muscles; and on the 
upper part of this margin we may remark a smooth surface, 
where the second head of the biceps flexor cubiti has its origin. 
The root of the margin is rough all around, for the firmer adhe- 
sion of the capsular ligament of the articulation, and of the car- 
tilage ; which is thick on the margin, but becomes very thin as 
it is continued towards the middle of the cavity, which it lines 
all over. 

The medullary vessels enter the scapula near the base of the 
spine. 

The substance of the scapula, as in all other broad flat bones, 
is cellular, but of an unequal thickness: for the neck and third 
process are thick and strong ; the inferior costa, spine, and cora- 
coid process, are of a middle thickness ; and the body is so 
pressed by the muscles, as to become thin and transparent. 

The scapula and clavicle are joined by plane surfaces, tipped 
with cartilage; by which neither bone is allowed any considera- 



jgQ THE SCAPULA. 

ble motion, being tightly tied down by the common capsular liga- 
ment, and by a very strong one which proceeds from the cora- 
coid process; but divides into two before it is fixed into the cla- 
vicle, with such a direction as can either allow this bone to have 
a small rotation, in which its posterior edge turns more back- 
wards, while the anterior one rises farther forwards ; or it can 
yield to the forepart of the scapula moving downwards, while 
the back part of it is drawn upwards : in both which cases, the 
oblong, smooth articulated surfaces of the clavicle and scapula 
are not in the same plane, but stand a little transversely, or 
across each other, and thereby preserve this joint from luxations, 
to which it would be subject if either of the bones were to move 
on the other perpendicularly up and down, without any rotation. 
Sometimes a movable ligamentous- cartilage is found in this 
joint ; and sometimes such a cartilage is only interposed at the 
anterior half of it; and in some old subjects a sesamoid bone has 
been found here. 

The scapula is connected to the head, os hyoides, vertebras, 
ribs, and arm bone, by muscles that have one end fastened to 
these parts, and the other to the scapula, which can move it up- 
wards, downwards, backwards, or forwards : by the quick suc- 
cession of these motions, its whole body is carried in a circle. 
But being also often moved, as upon an axis perpendicular to 
its plane, its circumference turns in a circle whose centre this 
axis is. Whichever of these motions it performs, it always car- 
ries the outer end of the clavicle and the arm along with it. 
The glenoid cavity of this bone receives the os humeri, which 
plays in it, as will be more fully explained hereafter. 

The use of the scapula is, to serve as a fulcrum to the arm ; and 
by altering its position on different occasions, to allow always to 
the head of the os humeri a socket to move in properly situated ; 
and thereby to assist and to enlarge greatly the motions of the 
superior extremity, and to afford the muscles which rise from it 
more advantageous actions, by altering their directions with re- 
spect to the bone which they are to move. This bone also serves 
to defend the back part of the thorax, and is often employed to 
sustain weights, or to resist forces too great for the arm to bear. 



THE OS HUMERI. 



161 



Os Humeri, or Arm bone. 

The arm has only one bone, best known by the Latin name of 
os humeri; which is long, round, and nearly straight. 

The upper end of this bone consists of a large round smooth 
head, which forms the segment of a sphere, whose axis is not in 
a straight line with the axis of the bone, but stands obliquely 
backwards from it. The extent of the head is distinguished by 
a circular fossa surrounding its base, where the head is united to 
the bone, and the capsular ligament of the joint is fixed. Below 
the forepart of its base, two tubercles stand out : the smaller one, 
which is situated most to the inside, has the tendon of the sub- 
scapulars muscle inserted into it. The larger more external 
protuberance is divided, at its upper part, into three smooth plane 
surfaces: into the anterior of which, the musculus supra-spina- 
tus ; into the middle or largest, the infra-spinatus ; and into the 
one behind, the teres minor, is inserted. Between these two tu- 
bercles, exactly in the forepart of the bone, a deep long groove 
is formed, for lodging the tendinous head of the biceps flexor cu- 
biti ; which, after passing, in a manner peculiar to itself, through 
the cavity of the articulation, is tied down, by a tendinous sheath 
extended across the groove ; in which, and in the neighbouring 
tubercles, are several remarkable holes, which are penetrated by 
the tendinous and ligamentous fibres, and by vessels. On each 
side of this groove, as it descends in the os humeri, a rough 
ridge, gently flattened in the middle, runs from the roots of the 
tubercles. The tendon of the pectoral muscle is fixed into the 
anterior of these ridges, and the latissimus dorsi and teres major 
are inserted into the internal one. A little behind the lower end 
of this last, another rough ridge may be observed, where the co- 
raco-brachialis is inserted. From the back part of the root of 
the largest tubercle, a ridge also is continued ; from which the 
extensor brevis cubiti arises. This bone is flattened on the in- 
side, about its middle, by the belly of the biceps flexor cubiti. In 
the middle of this plane surface, the entry of the medullary ar- 
tery is seen slanting obliquely downwards. x\t the foreside of 
this plane, the bone rises in a sort of ridge, which is rough, and 

14* 



jg2 THE 0S HUMERI. 

often has a great many small holes in it, where the strong del- 
toid muscle is inserted ; on each side of which the bone is smooth 
and flat, where the brachialus internus rises. The exterior of 
these two flat surfaces is the largest : behind it a superficial spi- 
ral channel, formed by the muscular nerve, and the vessels that 
accompany it, runs from behind forwards and downwards. 

The body of the os humeri is flattened behind by the extensors 
of the forearm. 

Near the lower end of this bone, a large sharp ridge is ex- 
tended on its outside; from which the musculus supinator radii 
longus, and the longest head of the extensor carpi radialis, arise. 
Opposite to this there is another small ridge to which the apo- 
neurotic tendon, that gives origin to the fibres of the internal and 
external brachial muscles, is fixed ; and from a little depression 
on the foreside of it, the pronator radii teres arises. 

The body of the os humeri becomes gradually broader towards 
the lower end, where it has several processes ; at the roots of 
which there is a cavity before, and one behind called sigmoid. 
The anterior is divided by a ridge into two; the external, which 
is the least, receives the end of the radius; and the internal re- 
ceives the coronoid process of the ulna, in the flexions of the 
forearm ; while the posterior deep triangular cavity lodges the 
olecranon in the extensions of that limb. The bone between 
these two cavities is pressed so thin by the processes of the ulna, 
as to appear transparent in many subjects. The sides of the 
posterior cavity are stretched out into two processes, one on 
each side. These are called condyles ; from each of which a 
strong ligament goes out to the bones of the forearm. The ex- 
ternal condyle, which has an oblique direction forwards with re- 
spect to the internal, when the arm is in the most natural pos- 
ture, is equally broad, and has an obtuse smooth head rising 
from it forwards. From the rough part of the condyle, several 
muscles arise; and on the smooth head the upper end of the 
radius plays. The internal condyle is more pointed and protu- 
berant than the external, to give origin to the flexor muscles of 
the wrist and hands, &c. Between the two condyles, is the 
trochlea, or pulley ; which consists of two lateral protuberances 



THE OS HUMERI. jgg 

and a middle cavity that are smooth, and covered with cartilage. 
When the forearm is extended, the tendon of the internal bra- 
chialus muscle is lodged in the forepart of the cavity of this pul- 
ley. The external protuberance, which is less than the other, has 
a sharp edge behind: but forwards, this ridge is obtuse, and only 
separated from the little head, already described, by a small 
fossa, in which the adjoining edges of the ulna and radius move. 
The internal protuberance of the pulley is largest and highest ; 
and therefore, in the motions of the ulna upon it, that bone would 
be inclined outwards, were it not supported by the radius on 
that side. Between this internal protuberance and condyle, a 
sinuosity may be remarked, where the ulnar nerve passes. 

The substance and the internal structure of the os humeri are 
the same, and disposed in the same way, as in the other long 
bones. 

The round head, at the upper end of this bone, is articulated 
with the glenoid cavity of the scapula; which being superficial, 
and having long ligaments, allows the arm a free and extensive 
motion. These ligaments are, however, considerably strong. 
For, besides the common capsular ligament, the tendons of the 
muscles perform the office, and have been described under the 
name of ligaments. Then the acromion and coracoid process, 
with the strong broad ligaments stretched between them, secure 
the articulation above ; where the greatest and most frequent 
force is applied, to thrust the head of the bone out of its place. 
It is true, that there is not near so strong a defence in the lower 
part of the articulation ; but, in the ordinary postures of the arm, 
that is, so long as it is an acute angle with the trunk of the body, 
there cannot be any force applied at this place to occasion a 
luxation, since the joint is protected so well above. 

The motions which the arm enjoys by this articulation, are to 
every side: and, by the succession of these different motions, a 
circle may be described. Besides which, the bone performs a 
small rotation round its own axis ; but, when the axis of the bone 
is the centre of motion, the movements are very different from 
those which take place when the axis of its head is the centre; 
for the axis of the head forms a very large angle with the axis 
of the body of the bone. Thus, when the arm swings back- 



164 U " NA 

wards and forwards, the axis of the head is the centre of motion ; 
but when the elbow is bent, and the forearm forms a right angle 
with the os humeri, the motion which applies the forearm to the 
thorax, or removes it, is a rotation of this bone on its axis. 

Though the motions of the arm seem to be very extensive, 
yet the larger share of them depends on the motions of the sca- 
pula ; for the surface of the glenoid cavity is directed upwards 
or downwards, and, to a certain degree, backwards or forwards, 
to support the head of the os humeri. This is exemplified when 
we press the hand against a body which is before, or above, or 
to one side of us. 

The lower end of the os humeri is articulated to the bones of 
the forearm, and carries them with it in all its motions; but 
serves as a base, on which they perform the motions peculiar to. 
themselves; as will shortly be described. 

The Forearm 

Consists of two bones, one of which is called ulna, from its 
being used as a measure; and the other radius, from the sup- 
posed resemblance to the spoke of a wheel. 

These bones are concerned in very different operations. The 
ulna forms the elbow joint with the os humeri ; the radius is the 
movable basis of the hand. 

Ulna. 

The length of this bone is equal to the forearm, of which it is 
a part. It is thickest above, and gradually diminishes until near 
its lower end. The body of the bone is nearly triangular in 
form. At the upper extremity of the ulna, on its anterior sur- 
face, is a semicircular notch. The end of the bone which forms 
the posterior part of this notch is denominated olecranon. The 
anterior part of the notch is formed by a process called coro- 
noid. This notch applies to the pulley-like surface on the inter- 
nal side of the lower extremity of the os humeri, to form the 
articulation of the elbow. In the middle of the concave surface 
is a ridge, in consequence of which, a small rocking motion is 
performed by the ulna. The external surface of the olecranon 
is rough, and strongly mark^ T 1 ^ aytvntmr miwr-lo ^f thA 



THE ULNA 



165 



forearm is inserted into the end of it, and below this is a flat 
surface on which we lean. On the outside of the coronoid pro- 
cess is a semilunated smooth cavity, lined with cartilage; in 
which, and in a ligament extended from the one to the other 
end of this cavity, the round head of the radius plays. Imme- 
diately below it, a rough hollow gives lodging to mucilaginous 
glands. Below the root of the coronoid process, this bone is 
scabrous and unequal, where the brachialus internus is inserted. 
On the outside of that, we observe a smooth concavity, where 
the beginning of the flexor digitorum profundus sprouts out. 

The external angle of the triangular part of the ulna is very 
sharp, where the ligament that connects the two bones is fixed: 
the sides which make this angle are flat and rough, by the action 
and adhesion of the many muscles which are situated here. At 
the distance of one-third of the length of the ulna from the top, 
in its forepart, the passage of the medullary vessels may be seen 
slanting upwards. The internal side of this bone is smooth, 
somewhat convex, and the angles at each edge of it are blunted 
by the pressure of the muscles equally disposed about them. 

As this bone descends, it becomes gradually smaller; so that 
its lower end terminates in a little head, standing on a small 
neck: towards the inner and back part of which last, an oblique 
ridge runs, that gives rise to the pronator radii quadratus. The 
head is sometimes cylindrical, smooth, and covered with a car- 
tilage on its external side, to be received into the semilunar 
cavity of the radius ; while a styloid process rises from its in- 
side, to which is fixed a strong ligament that is extended to the 
os cuneiforme and pisiforme of the wrist. At the root of the 
process, the end of the bone is smooth, and covered with a car- 
tilage. Between it and the bones of the wrist, a doubly concave 
movable cartilage is interposed ; which is a continuation of the 
cartilage that covers the lower end of the radius, and is con- 
nected loosely to the root of the styloid process, and to the rough 
cavity there; in which mucilaginous glands* are lodged. 

The ulna is principally concerned in the articulation with the 

* All these so called glands are mere masses of adipose matter, supposed, though 
wrongly, by Havers to be the glands which secrete the synovia. — p. 



j(jg RADIUS. 

os humeri, and forms a hinge-like joint, which allows extension 
nearly to a straight line, and flexion to an acute angle. By the 
sloping of the pulley-like surface, the lower part of the arm is 
turned outwards in the extension, and inwards in the flexion ; 
which greatly facilitates the motion of the hand towards the 
head. 

Radius. 

Before the radius is described, it is necessary to observe that the lower end 
of this bone occasionally revolves half round the lower end of the ulna, 
and the hand with it. The relative situation of these parts is, therefore, 
different in different positions of the hand. In the following description, 
the palm of the hand is supposed to present forwards, and the thumb out- 
wards ; in which case, the two bones of the forearm will be parallel to 
each other. 

The radius is situated on the outside of the forearm, and is 
rather shorter than the ulna. Its extremities are the reverse of 
those of the ulna in their proportionate size; and the body is not 
triangular, although it approaches towards that form. Its upper 
end is formed into a cylindrical head, which is hollowed on the 
top for an articulation with the tubercle at the side of the pulley 
of the os humeri ; and the half cylindrical circumference next 
to the ulna is smooth, and covered with a cartilage, in order to 
be received into the semilunated cavity of that bone. Below the 
head, the radius is much smaller; and, therefore, this part is 
named its cervix. At the internal root of this neck is a flat 
tubercle, into the inner part of which the biceps flexor cubiti is 
inserted. From this a ridge runs downwards and outwards 
where the supinator radii brevis is inserted ; and a little below, 
and behind this ridge, there is a rough scabrous surface, where the 
pronator radii teres is fixed. 

The body of the radius is not straight, but curved externally 
the greater part of its length. Its external surface is rounded ; 
the anterior and posterior surfaces are flattened ; and between 
them is a sharp spine, to which the strong ligament extended 
between the two bones of the forearm is fixed. On the anterior 
surface, at a distance from its head, nearly equal to one-third 



RADIUS. jg7 

the length of the bone, is the orifice of the canal for the medul- 
lary vessels, which has a direction obliquely upwards. 

Towards the lower end the radius becomes broader and flatter, 
especially on its forepart, where the pronator quadratus muscle 
is situated. Its back part, at this end, has a flat strong ridge in 
the middle, and fossa? on each side. In a small groove, imme- 
diately on the inside of the ridge, the tendon of the extensor of 
the last joint of the thumb plays, In a large one, inside of this, 
the tendons of the indicator, and of the common extensor 
muscles of the fingers pass. On the outside of the ridge there 
is a broad depression, which seems again subdivided, where the 
two tendons of the extensor carpi radialis are lodged. The ex- 
ternal side of this end of the radius is also hollowed by the ex- 
tensors of the first and second joints of the thumb. The ridges 
at the sides of the grooves, in which the tendons play, have an 
annular ligament fixed to them, by which the several sheaths 
for the tendons are formed. The forepart of this end of the 
radius is also depressed, where the flexors of the fingers and 
flexor carpi radialis pass. The internal side is formed into a 
semilunated smooth cavity, lined with a cartilage, for receiving 
the lower end of the ulna. The lowest part of the radius is 
formed into an oblong cavity; in the middle of which is a 
small transverse rising, gently hollowed, for lodging mucilagi- 
nous glands ; while the rising itself is insinuated into the con- 
junction of the two bones of the wrist that are received into the 
cavity. The external side of this articulation is defended by a 
remarkable process of the radius, from which a ligament passes 
to the wrist ; and this structure resembles that of the styloid 
process of the ulna with its ligament. 

The ends of both the bones of the forearm being thicker than 
the middle, and the radius being curved, there is a considerable 
distance between the bodies of these bones; in the larger part 
of which a strong, tendinous, but thin ligament, is extended, to 
give a sufficient surface for the origin of the numerous fibres of 
the muscles situated here, that are so much sunk between the 
bones as to be protected from injuries, to which they would 
otherwise be exposed. But this ligament is wanting near the 



168 



THE HAND. 



upper end of the forearm, where the supinator radii brevis and 
flexor digitorum profundus, are immediately connected. 

As the head of the radius receives the tubercle of the os 
humeri, it is not only bended and extended along with the ulna, 
but may be moved almost half round its axis ; and that this 
motion round its axis may be sufficiently large, the ligament 
of the articulation is extended farther down than ordinary, on 
the neck of this bone, before it. is connected to it; and it is 
very thin at its upper and lower part, but makes a firm ring 
in the middle. This bone is also joined to the ulna by a double 
articulation : for above, a tubercle of the radius plays in a socket 
of the ulna ; whilst below, the radius gives the socket, and the 
ulna the tubercle. But then the motion performed at the two 
ends is very different : for, at the upper end, the radius does little 
more than turn round its axis; while, at the lower end, it moves 
nearly half round the cylindrical end of the ulna ; and, as the 
hand is articulated and firmly connected here with the radius, 
they must move together. When the palm is turned uppermost, 
the radius is said to perform supination: when the back of the 
hand is above, it is said to be prone. But then the quickness and 
large extent of these two motions are assisted by the ulna, which, 
as was before observed, can move with a kind of small rotation 
on the sloping sides of the pulley. This rocking motion, though 
very inconsiderable in the elbow joint itself, is conspicuous at the 
lower end of such a long bone ; and the strong ligament con- 
necting this lower end to the carpus, makes the hand more 
readily obey these motions. 

The Hand. 

The hand comprehends the whole structure, from the end of 
the radius to the points of the fingers. Its back part is convex, 
for greater firmness and strength ; and it is concave before, for 
containing more surely and conveniently such bodies as we take 
hold of. One half of the hand has an obscure motion in com- 
parison of what the other has ; it serves as a base to the mova- 
ble half, which can be extended back verv little farther than to a 



CARPUS. , fi g 

straight line with the forearm, but can be considerably bent for- 
wards. 

The hand consists of the carpus or wrist; metacarpus, or 
part adjoining the wrist ; and the fingers, among which the thumb 
is reckoned. 

Carpus. 

No part of the skeleton is more complex than the carpus. The following 
description will, therefore, be of little use to a young student, unless the 
bones are before him when he is reading it. Great advantage will be de- 
rived from examining two sets of carpal bones: each set belonging to the 
same side. In one of these sets the bones should be connected by their 
natural ligaments; but the two rows separated from each other. The 
bones of the other set should be accurately cleaned, so that their forms 
and surfaces may be examined. 

The carpus is composed of eight small bones, arranged in two 
rows ; one of which rows is attached to the bones of the fore- 
arm, and the other to the body of the hand. 

These bones are named from their figure, and shall be men- 
tioned in the order in which they occur, beginning with the row 
next to the forearm ; and with the external bone in each row. 

They are, Os Scaphoides, Lunare, Cuneiforme, Pisiforme, 
forming the upper row ; Os Trapezium, Trapewides, Magnum, 
and Unciforme, forming the lower row. 

First Row. 

Os scaphoides is the largest of the eight, excepting one. It is 
convex above, concave and oblong below; from which small 
resemblance to a boat, it has got its name. Its smooth convex 
surface is divided by a rough middle fossa, which runs obliquely 
across it. The upper largest division is articulated with the radius. 
The common ligament of the joint of the wrist is fixed into the 
fossa; and the lower division is joined to the trapezium and tra- 
pezoides. The concavity receives more than half of the round 
head of the os magnum. The internal side of this hollow is 
formed into a semilunar plane to be articulated with the follow- 
ing bone. The external, posterior, and anterior edges are rough, 
for fixing the ligaments that connect it to the surrounding bones. 

vol. i. 15 



270 CARPUS. 

Os lunare has a smooth convex upper surface, by which it is 
articulated with the radius. The external side, which gives the 
name to the bone, is in the form of a crescent, and is joined 
with the scaphoid : the lower surface is hollow, for receiving 
part of the head of the os magnum. On the inside of this cavity 
is another smooth, but narrow, oblong sinuosity, for receiving 
the upper end of the unciforme: and on the inside of this a 
small convexity is found, for its connexion with the os cunei- 
forme. Between the great convexity above, and the first deep 
inferior cavity, there is a rough fossa, in which the circular liga- 
ment of the joint of the wrist is fixed. 

Os cuneiforme is broader above, and towards the back of the 
hand, than it is below and forwards ; which gives it the resem- 
blance of a wedge. The superior slightly convex surface is in- 
cluded in the joint of the wrist, being opposed to the lower end 
of the ulna. Below this the cuneiforme bone has a rough fossa, 
wherein the ligament of the articulation of the wrist is fixed. 
On the external side of this bone, where it is contiguous to the 
os lunare, it is smooth, and slightly concave. Its lower surface, 
where it is contiguous to the os unciforme, is oblong, somewhat 
spiral, and concave. Near the middle of its anterior surface, a 
circular plane appears, where the os pisiforme is sustained. 

Os pisiforme is almost spherical, except one circular plane, or 
slightly hollowed surface, which is covered with cartilage for 
its motion on the cuneiforme bone, from which its whole rough 
body is prominent forwards into the palm ; having the tendon of 
the flexor carpi ulnaris, and a ligament from the styloid process 
of the ulna fixed to its upper part ; the transverse ligament of 
the wrist is connected to its external side : ligaments extended to 
the unciforme bone, and to the os metacarpi of the little finger, 
are attached to its lower part ; the abductor minimi digiti has 
its origin from its forepart ; and, at the external side of it, a 
small depression is formed for the passage of the ulnar nerve. 

Second Row. 

Os Trapezium has four unequal sides and angles in its back 
part, from which it has got its name. Above, its surface is smooth, 
slightly hollowed, and semicircular, for its conjunction with the 



CARPUS. 



171 



os scaphoides. Its internal side is an oblong concave square, 
for receiving the following bone. The inferior surface is formed 
into a pulley, which faces obliquely outwards and downwards 
when the palm presents forward. On this pulley the first bone of 
the thumb is moved. 

At the internal side of the pulley, a small oblong smooth sur- 
face is formed by the os metacarpi indicis. The forepart of the 
trapezium is prominent in the palm, and near to the internal side 
has a sinuosity in it, where the tendon of the flexor carpi radialis 
is lodged, qn the ligamentous sheath of which the tendon of the 
flexor longus pollicis manus plays : near this the bone is sca- 
brous, where the transverse ligament of the wrist is connected, 
the abductor and the flexor brevis pollicis have their origin, and 
ligaments go out to the first of the thumb. 

Os trapezoides, so called from the irregular quadrangular figure 
of its back part, is the smallest bone of the wrist, except the 
pisiforme. The figure of it is an irregular cube. It has a small 
hollow surface above, by which it joins the scaphoides; a long 
convex one externally, where it is contiguous to the trapezium ; 
a small internal concavity, for its conjunction with the os mag- 
num; and an inferior convex surface, the edges of which are, 
however, so raised before and behind, that a sort of pulley is 
formed, where it sustains the os metacarpi indicis. 

Os magnum, so called because it is the largest bone of the 
carpus, is oblong, having four quadrangular sides, with a round 
upper end, and a triangular plane one below. The round head 
is divided by a small rising, opposite to the connexion of the os 
scaphoides and lunare, which together form the cavity for re- 
ceiving it. On the outside a short plane surface joins the os 
magnum to the trapezoides. On the inside is a long narrow con- 
cave surface where it is contiguous to the os unciforme. The 
lower end, which sustains the metacarpal bone of the middle 
finger, is triangular, slightly hollowed, and farther advanced on 
the external side than on the internal, having a considerable ob- 
long depression made on the advanced outside by the metacarpal 
bone of the fore-finger ; and generally there is a small mark of 
the os metacarpi digiti annularis on its internal side, 



j«0 CARPUS. 

Os unciforme has got its name from a thin broad process that 
stands out from it forwards into the palm, and is hollow, for af- 
fording passage to the tendons of the flexors of the fingers. To 
this process, also, the transverse ligament is fixed that binds 
down, and defends these tendons ; and the flexor and abductor 
muscles of the little finger have part of their origin from it. 
The upper plane surface is small, convex, and joined with the os 
lunare: the external side is long and slightly convex, adapted to 
the contiguous os magnum. The internal surface is oblique, 
and irregularly convex, to be articulated with the cuneiforme 
bone. The lower end is divided into two concave surfaces ; the 
internal is joined with the metacarpal bone of the little finger ; 
and the external one is fitted to the metacarpal bone of the ring 
finger. 

The nature of the carpus will be best understood by studying 
the bones placed together, in their natural order, in the two 
rows. 

When thus placed, they compose a structure of an oblong 
form, whose greatest length extends across the wrist, and forms 
a concavity in front, while it is convex posteriorly. 

Two bones of the first row, viz. the scaphoides and lunare, 
form an oblong convex surface, which has a transverse position 
with respect to the arm, and applies to the concave surface at 
the end of the radius. These surfaces are particularly calcu- 
lated for flexion and extension, and also for a considerable motion 
to each side; and by a succession of these flexures, in different 
directions, the hand performs a circular motion, although it can- 
not perform at this joint a rotation, or revolution, on the axis of 
the carpus. 

The under surface of these bones has a deep concavity, which 
is composed by the scaphoides, lunare and cuneiforme, and re- 
ceives a prominence of the second row. It also presents a con- 
vex surface, formed by the scaphoides, which is received bv the 
second row. 

The upper surface of the second row, which is concerned in 
this articulation, is very irregular ; it has a head formed by the 
magnum and unciforme, which penetrates deeply into the cavity 



THE METACARPUS. 



173 



of the first row. On the outside of this head the trapezium and 
trapezoides form a surface, which receives the projecting part of 
the scaphoides ; so that the first row receives, and is received by 
the second, and the two surfaces are well calculated for moving, 
to a certain extent, in the way of flexion and extension, upon 
each other. 

The lower surface of the second row, which is connected to 
the metacarpal bones, appears like the side of an arch, which is 
partly induced by the wedge-like form of the two bones in the 
centre ; viz. the trapezoides, and the magnum. When the hand 
hangs by the side, and the palm is forward, all of this surface 
presents downwards, except that portion of it which is formed 
by the trapezium. This bone is placed obliquely between the 
two rows, and its surface for supporting the thumb presents ob- 
liquely downwards and outwards. 

The trapezoides supports the fore-finger, the magnum the 
middle finger. 

The scaphoides and the trapezium are very prominent at the 
external side of the anterior concave surface of the carpus ; and 
the unciforme process, and the os pisiforme on the internal. 

The Metacarpus, 

Consists of four bones, which sustain the fingers. Each bone 
is long and round, with its ends larger than its body. The up- 
per end, which some call the base, is flat and oblong, inclining 
somewhat to the wedge-like form, without any considerable head 
or cavity ; but it is, however, somewhat hollowed for the articu- 
lation with the carpus. It is made flat and smooth on the sides 
where these bones are contiguous to each other. Their bodies 
are flattened on the back part, particularly below the middle, by 
tendons of the extensors of the fingers. The anterior surface of 
these bodies is a little convex, especially in their middle ; along 
which a sharp ridge stands out, separating the musculi interossei 
placed on each side of these bones, which are there made flat 
and plain by these muscles. 

Their lower ends are raised into large oblong smooth heads> 
whose greatest extent is forwards from the axis of the bone. At 

15* 



174 



THE METACARPUS. 



the forepart of each side of the root of these heads, one or two 
tubercles stand out, for fixing the ligaments that go from one 
metacarpal bone to another, to preserve them from being drawn 
asunder. Around the heads a rough ring may be remarked, 
for the capsular ligaments of the first joints of the fingers to be 
fixed to; and both sides of these heads are flat, by pressing on 
each other. 

The substance of the metacarpal bones is the same with that 
of all long bones. 

The metacarpal bones are joined above to the bones of the 
carpus, and to each other by surfaces almost flat. These con- 
nexions do not admit of much motion. The articulation of 
the round heads, at their lower ends, with the cavities of the 
first bones of the fingers, will soon be described. 

The concavity on the forepart of the metacarpal bones, and 
the position of their bases on the arched carpus, cause them to 
form a hollow in the palm of the hand, which is often useful to 
us. The spaces between them lodge muscles, and their small 
motion makes them fit supporters for the fingers to play on. 

Though the ossa metacarpi so far agree, yet they may be dis- 
tinguished from each other by the following marks : 

The metacarpal bone of the fore-finger is generally the longest. 
Its base, which is articulated with the os trapezoides, is hollow 
in the middle. The small ridge on the external side of this 
oblong cavity is smaller than the one opposite to it, and is made 
flat on the side by the trapezium. The internal ridge is also 
smooth, and flat on its ulnar side, for its conjunction with the os 
magnum ; immediately below which, a semicircular smooth flat 
surface shows the articulation of this to the second metacarpal 
bone. The back part of this base is flattened where the long head 
of the extensor carpi radialis is inserted, and its forepart is pro- 
minent where the tendon of the flexor carpi radialis is fixed. 
The tubercle at the internal root of its head is larger than the 
external. Its base is so firmly fixed to the bone it is connected 
with, that it has no motion. 

The metacarpal bone of the middle finger is generally the se- 
cond in length; but often it is as long as the former: sometimes 



THE METACARPUS. 



175 



it is longer ; and it frequently appears only to equal the first by 
the os magnum being farther projected downwards than any 
other bone of the wrist. Its base is a broad superficial cavity, 
slanting inwards ; the external posterior angle of which is so 
prominent, as to have the appearance of a process. The exter- 
nal side of this base is made plane in the same way as the exter- 
nal side of the former bone, while its internal side has two hol- 
low circular surfaces, for joining the third metacarpal bone ; and 
between these surfaces there is a rough fossa, for the adhesion of 
a ligament, and lodging mucilaginous glands. The extensor 
carpi radialis brevior is inserted into the back part of this base. 
The two sides of this bone are almost equally flattened ; but the 
ridge on the forepart of the body inclines inwards. The tu- 
bercles at the forepart of the root of the head are equal. The 
motion of this bone is very little more than that of the former; 
and therefore these two firmly resist bodies pressed against them 
by the thumb or fingers, or both. 

The metacarpal bone of the ring finger is shorter than the se- 
cond metacarpal bone. Its base is semicircular and convex, 
for its conjunction with the os unciforme. On its external side 
are two smooth convexities, and a middle fossa, adapted to the 
second metacarpal bone. The internal side has a triangular 
smooth concave surface to join it with the fourth one. The an- 
terior ridge of its body is situated more to the inside than to the 
outside. The tubercles near the head are equal. The motion of 
this third metacarpal bone is greater than the motion of the se- 
cond. 

The metacarpal bone of the little finger is the smallest and 
sharpest. Its base is irregularly convex, and rises slanting in- 
wards. Its external side is exactly adapted to the third meta- 
carpal bone. The internal has no smooth surface, because it is 
not contiguous to any other bone ; but it is prominent where the 
extensor carpi ulnaris is inserted. As this metacarpal bone is 
furnished with a proper moving muscle, has the plainest articu- 
lation, is most loosely connected and least confined, it not only 
enjoys a much larger motion than any of the rest, but draws the 
third bone with it, when the palm of the hand is to be made hoi- 



176 THUMB AND FINGERS. 

low by its advancement forwards, and by the prominence of the 
thumb opposite to it 

Thumb and Fingers. 

The thumb and fore-fingers are each composed of three bones. 

The thumb is situated obliquely in respect to the fingers; 
neither opposite directly to them, nor in the same plane with 
them. All its bones are much thicker and stronger in propor- 
tion to their length, than the bones of the fingers are; which is 
extremely necessary, as the thumb counteracts all the fingers. 

The first bone of the thumb has its base adapted to the pecu- 
liar articulating surface of the trapezium ; for, in viewing it from 
one side to the other, it appears convex in the middle ; but, when 
viewed from behind forwards, it is concave there. The edge at 
the forepart of this base is extended farther than any other part; 
and round the back part of the base a rough fossa may be seen, 
for the connexion of the ligaments of this joint. The body and 
head of this bone are of the same shape as the ossa metacarpi; 
only that the body is shorter, the head flatter, and tubercles at 
the forepart of its root larger. 

The articulation of the upper end of this bone is remarkable ; 
for, though it has protuberances and depressions adapted to the 
double pulley of the trapezium, yet it enjoys a circular motion, 
as the joints do where a round head of the one plays in the orbi- 
cular socket of another: it is, however, more confined, and less 
expeditious, but stronger and more secure than such joints gene- 
rally are. 

The second bone of the thumb has a large base formed into 
art oblong cavity, whose greatest length is from one side to the 
other. Round it several tubercles may be remarked, for the in- 
sertion of ligaments. Its body is convex, or half round behind; 
but flat before, for lodging the tendon of the long flexor of the 
thumb, which is tied down by ligamentous sheaths, that are 
fixed on each side to the angle at the edge of this flat surface. 
The lower end of this second bone has two lateral round protu- 
berances, and a middle cavity, whose greatest extent of smooth 
surface is forwards and backwards. 



FINGERS j~~ 

The articulation of the upper end of this second bone would 
seem calculated for motion in all directions; yet, on account of 
the strength of its lateral ligaments, the oblong figure of the joint 
itself, and mobility of the first joint, it only allows flexion and 
extension ; and these are generally much confined. 

The third bone of the thumb is the smallest, with a large base, 
whose greatest extent is from one side to the other. This base 
is formed into two cavities and a middle protuberance, to be 
adapted to the pulley of the former bone. This bone becomes 
gradually smaller, till near the lower end, where it is a little 
enlarged, and has an oval scabrous edge. Its body is rounded 
behind, but is flatter than in the former bone, for sustaining the 
nail. It is flat and rough before, by the insertion of the flexor 
longus pollicis. 

The motion of this third bone is confined to flexion and ex- 
tension. 

The regular arrangement of the bones of the fingers in three 
rows, has obtained for them the name of the three -phalanges. 
All of them have half round convex surfaces, covered with an 
aponeurosis, formed by the tendons of the extensors, lumbricales, 
and interossei, and placed directly backwards, for their greater 
strength ; and their flat concave part is forwards, for taking 
hold more surely, and for lodging the tendons of the flexor mus- 
cles. The ligaments for keeping down these tendons are fixed 
to the angles that are between the convex and concave sides. 

The bones of the first phalanx of the fingers answer to the 
description of the second bone of the thumb; only that the cavity 
in their base is not so oblong; nor is their motion on the meta- 
carpal bones so much confined ; for they can move laterally or 
circularly, the fore-finger in particular, but have no rotation, or 
a very small degree of it, round their axis. 

The second bone of the fingers has its base formed into two 
lateral cavities, and a middle protuberance: while the lower end 
has two lateral protuberances, and a middle cavity ; therefore, 
it is joined at both ends in the same manner; which none of the 
bones of the thumb are. 

The third bone differs nothing from the description of the third 



J7Q THE THIGH. 

bone of the thumb, except in the general distinguishing marks ; 
and, therefore, the second and third phalanx of the fingers enjoy 
only flexion and extension. 

All the difference of the phalanges of the several fingers con- 
sists in their magnitude. The bones of the middle finger being 
the longest and largest; those of the fore-finger come next to 
these in thickness, but not in length, for those of the ring finger 
are a little longer. The little finger has the smallest bones. 
Which disposition is the best contrivance for holding the largest 
bodies; because the longest fingers are applied to the middle 
largest periphery of such substances as are of a spherical figure. 

The Inferior Extremities. 
The inferior extremities consist of the Thigh, Leg, and Foot. 

The Thigh. 

Consists of one bone only ; the os femoris, which is very 
strong, and larger than any other in the skeleton. It is nearly 
cylindrical in the middle, and slightly curved. The upper ex- 
tremity is a spherical head, connected to the body of the bone 
by a neck. The lower extremity is much larger than the body, 
and is formed into two condyles. 

The upper end of this bone is not continued in a straight line 
with the body of it, but the axis of it inclines obliquely inwards 
and upwards, whereby the distance between these two bones, at 
their upper part, is considerably increased. The head is the 
greater portion of a sphere. Towards its lower internal part, a 
round, rough, spongy pit is observable, where the strong liga- 
ment, commonly, but inaccurately, called the round one, is fixed, 
to be extended from thence to the lower internal part of the re- 
ceiving cavity, where it is considerably broader than near to 
the head of the thigh bone. The neck of the os femoris has a 
great many large holes, into which the fibres of the strong liga- 
ment, continued from the capsular, enter, and are thereby firmly 
united 'to it ; and round the root of the neck, where it rises from 
the bone, a rough ridge is found, where the capsular ligament 
of the articulation itself is connected. Below this root, a large 



THE THIGH. jaq 

unequal protuberance, called trochanter major, stands out ; the 
external convex part of which is distinguished into three different 
surfaces; whereof the one on the upper and front part is sca- 
brous and rough, for the insertion of the glutaeus minimus; the 
superior one is smooth, and has the glutseus medius inserted into 
it; and the one behind is made flat and smooth, by the tendon 
of the glutseus maximus passing over it. The upper edge of 
this process is sharp and pointed at its back part, where the 
glutaeus medius is fixed ; but forwards it is more obtuse, and 
under it is a depression, into which some of the muscles, which 
rotate the thigh outwards, are fixed. From the posterior pro- 
minent part of this great trochanter, a rough ridge runs back- 
wards and downwards, into which the quadratus is inserted. In 
the deep hollow, at the internal upper side of this ridge, the ob- 
turator externus is implanted. More internally, a conical pro- 
cess, called trochanter minor, rises, for the insertion of the mus- 
culus psoas and iliacus internus ; and the pectineus is implanted 
into a rough hollow, below its internal root. The muscles inserted 
into these processes being the principal instruments of the rotary 
motion of the thigh, have occasioned the name of trochanters to 
be given to these processes. 

The body of the os femoris is convex on the forepart and 
concave behind, which enables us to sit without leaning too much 
on the posterior muscles. 

On the posterior concave surface is a broad rough ridge 
called linea aspera, which commences near the great trochanter, 
and continues downwards, more than two-thirds of the length of 
the bone, when it divides into two ridges, which descend towards 
each condyle. The internal of these ridges is the most smooth, 
and the space between them is nearly flat. Near the end of 
each of these ridges, a small, smooth protuberance may often 
be remarked, where the two heads of the external gastrocne- 
mius muscle take their rise; and from the forepart of the in- 
ternal tubercle, a strong ligament is extended to the inside of the 
tibia. 

The lower end of the os femoris is larger than any other part 
of it, and is formed into two great protuberances, one on each 



1QQ OS FEMORIS. 

side, which are called its condyles: between them a considerable 
cavity is found, especially at the back part, in which the crural 
vessels and nerves lie. The internal condyle is longer than the 
external, which must happen from the oblique position of this 
bone, to give less obliquity to the leg. These processes are of 
an oblong form, and are placed obliquely with respect to each 
other; being in contact before and separated to a considerable 
distance behind. 

They form in front a smooth pulley-like surface, the external 
side of which is highest, on which the patella moves. 

Below, they are flat ; and posteriorly, they are regularly con- 
vex. 

Between these convex portions is a rough cavity, from which 
the crucial ligament arises, to be attached to the tibia. Round 
the lower end of the thigh bone, large holes are found, into 
which the ligaments for the security of the joint are fixed, and 
blood-vessels pass to the internal substance of the bone. 

The thigh bone being articulated above with the acetabulum 
of the os innominatum, which affords its round head a secure 
and extensive play, can be moved to every side: but it is re- 
strained in its motion outwards by the high brims of the cavity, 
and by the round ligament ; for otherwise the head of the bone 
would have been frequently thrust out at the breach of the brims 
on the inside, which allows the thigh to move considerably in- 
wards. The body of this bone enjoys little or no rotary motion, 
though the head most commonly moves round its own axis; be- 
cause the oblique direction of the neck and head from the bone, 
is such, that the rotary motion of the head can only bring the 
body of the bone forwards and backwards. Nor is the head, as 
in the arm, ever capable of being brought to a straight direction 
with its body ; so far, however, as the head can move within the 
cavity backwards and forwards, the rest of the bone may have 
a partial rotation. 

From the oblique position of these bones it results, that there 
is a considerable distance between them above, while the knees 
are almost contiguous. Sufficient space is thereby left for the 
external parts of generation, for the two great outlets of urine 



THE TIBIA. 



181 



and faeces, and for the large thick muscles that move the thigh 
inwards. At the same time this situation of the thigh bone 
renders our progression quicker, surer, straighter, and in less 
room : for, had the knees been at a greater distance from each 
other, we must have been obliged to describe some part of a 
circle with the trunk of our body in making a long step ; and 
when one leg was raised from the ground, our centre of gravity 
would have been too far from the base of the other, and we 
should consequently have been in danger of falling ; so that our 
steps would neither have been straight nor firm, nor would it 
have been possible to walk in a narrow path, had our thigh 
bones been otherwise placed. In consequence, however, of the 
weight of the body bearing so obliquely on the joint of the knee 
by this situation of the thigh bones, weak rickety children be- 
come knock-kneed. 

The Leg 

Is composed of the two bones, the tibia and fibula. 
The patella being evidently appropriated to the knee-joint, may 
be regarded as common both to the thigh and leg. 

The Tibia 

Is the long thick triangular bone, situated at the internal part 
of the leg, and continued in almost a straight line from the thigh 
bone. The name is derived from its resemblance to the ancient 
musical instrument. 

The upper end of the tibia is large, bulbous, and spongy. It 
has a horizontal surface, divided into two cavities, by a rough, 
irregular protuberance, which is hollow at its most prominent 
part, as well as before and behind. The anterior of the two 
ligaments that compose the great crucial is inserted into the 
middle cavity ; and the depression behind receives the posterior 
ligament. The two broad cavities at the sides of this protube- 
rance are not equal ; for the internal is oblong and deep, to re- 
ceive the internal condyle of the thigh bone; while the external 
is more superficial and round, for the external condyle. In each 
of these two cavities of a recent subject, a semilunar cartilage 

vol. i. 16 



182 TIBIA - 

is placed, which is thick at its convex edge, and becomes 
gradually thinner towards the concave or interior edge. The 
thick convex edge of each cartilage is connected to the capsular 
and other ligaments of the articulation; but so near to their rise 
from the tibia, that the cartilages are not allowed to change 
their places ; while their narrow ends are fixed at the insertion 
of the strong cross ligament into the tibia, and seem to have their 
substance uii4ted with it ; therefore a circular hole is left between 
each cartilage and the ligament, in which the most prominent 
convex part of each condyle of the thigh bone moves. The cir- 
cumference of these cavities is rough and unequal, for the firm 
connexion of the ligaments of the joint. Immediately below the 
edge, at its back part, two rough flattened protuberances stand 
out; into the internal, the tendon of the semimembranosus muscle 
is inserted ; and a part of the cross ligament is fixed to the ex- 
ternal. On the outside of this last tubercle, a smooth slightly 
hollowed surface is formed by the action of the poplitseus 
muscle. 

Before the forepart of the upper end of the tibia, a large 
rough protuberance rises, to which the strong tendinous liga- 
ment of the patella is fixed. On the internal side of this, there is 
a broad scabrous slightly hollowed surface, to which the internal 
long ligament of the joint, the aponeurosis of the vastus interims, 
and the tendons of the semitendinosus, gracilis, and sartorius, are 
fixed. Below the external edge of the upper end of the tibia, 
there is a flat circular surface, covered in a recent subject with 
cartilage, for the articulation of the fibula. The body of the 
tibia is triangular. The anterior angle is very sharp, and is 
commonly called the spine or shin. This ridge is not straight; 
but turns first inwards, then outwards, and lastly inwards again. 
The plane internal side is smooth and equal, being little subjected 
to the actions of muscle ; but the external side is hollowed above 
by the tibialis anticus, and below by the extensor digitorum 
longus and extensor pollicis longus. The two angles behind 
these sides are rounded by the action of the muscles ; the pos- 
terior side comprehended between them is not so broad as those 
already mentioned, but is more oblique and flattened by the 



FIBULA. igg 

action of the tibialis posticus and flexor digitorum longus. A 
little above the middle of the bone, the internal angle terminates, 
and the bone is made round by the pressure of the musculus 
solaeus. Near to this, the passage of the medullary vessels is 
seen slanting obliquely downwards. 

The lower end of the tibia is hollowed, with a small protu- 
berance in the middle. The internal side of this cavity, which 
is smooth, and in a recent subject is covered with cartilage, is 
extended into a considerable process, commonly named malleolus 
interims ; the point of which is divided by a notch, and from it 
ligaments are sent out to the foot. The external side of this 
end of the tibia has a rough irregular cavity formed in it, for re- 
ceiving the lower end of the fibula. The posterior side has two 
lateral grooves, and a small middle protuberance. In the internal 
depression, the tendons of the musculus tibialis posf.icis and flexor 
digitorum longus are lodged ; and in the external, the tendon of 
the flexor longus pollicis plays. From the middle protuberance, 
ligamentous sheaths go out, for tying down these tendons. 

The Fibula 

Is the small bone, placed on the outside of the leg, opposite to 
the external angle of the tibia ; the shape of it is irregular. 

The head of the fibula has a circular surface formed on its 
inside, which, in a recent subject is covered with a cartilage ; 
and it is so closely connected to the tibia by ligaments, as to 
allow only a very small motion backwards and forwards. This 
head is protuberant and rough on its outside, where a strong 
round ligament and the musculus biceps are inserted, and, 
below the back part of its internal side, a tubercle may be re- 
marked, that gives rise to the strong tendinous part of the solseus 
muscle. 

The body of this bone is a little crooked inwards and back- 
wards: which figure is owing to the actions of the muscles. 
The sharpest angle of the fibula is forwards ; on each side of 
which the bone is considerably, but unequally, depressed by the 
bellies of the several muscles that rise from or act upon it. The 
external surface of the fibula is depressed obliquely from above 



184 



FIBULA. 



downwards and backwards, by the two peronaei. Its internal 
surface is unequally divided into two narrow longitudinal planes, 
by an oblique ridge extended from the upper part of the anterior 
angle. To this ridge the ligament stretched between the two 
bones of the leg is connected. The anterior of the two planes is 
very narrow above, where the extensor longus digitorum and 
extensor longus pollicis arise from it: but is broader below, 
where it has the print of the nonus vesalii. The posterior plane 
is broad and hollow, giving origin to the larger share of the 
tibialis posticus. The internal angle of this bone has a tendinous 
membrane fixed to it, from which some fibres of the flexor digi- 
torum longus take their rise. The posterior surface of the fibula 
is the plainest and smoothest ; but is made flat above by the 
soJgeus, and is hollowed below by the flexor pollicis longus. In 
the middle of this surface, the canal for the medullary vessels 
may be seen slanting downwards. 

The lower end of the fibula is extended into a spongy oblong 
head : on the inside of which is a convex, irregular, and fre- 
quently a scabrous surface, that is received by the external hol- 
low of the tibia, and so firmly joined to it by a very thin inter- 
mediate cartilage and strong ligaments, that it scarce can move. 
Below this the fibula is stretched out into a smooth coronoid pro- 
cess, covered with cartilage on its internal side, and is there con- 
tiguous to the outside of the first bone of the foot, the astragalus, 
to secure the articulation. This process, named malleolus exter- 
nus, being situated farther back than in the internal malleolus, 
and in an oblique direction, obliges us, naturally, to turn the 
forepart of the foot outwards. At the lower internal part of this 
process, a spongy cavity for mucilaginous glands may be re- 
marked ; from its point, ligaments are extended to the bones of 
the foot, viz. the astragalus, os calcis, and os naviculare ; and 
from its inside short strong ones go out to the astragalus. On 
the back part of it a sinuosity is made by the tendons of the pe- 
ronasi muscles. When the ligament, extended over these tendons 
from the one side of the depression to the other, is broken, 
stretched too much, or made weak by the sprain, the tendons 
frequently start forwards to the outside of the fibula. 



THE PATELLA OR ROTULA. jgg 

The conjunction of the upper end of the fibula with the tibia 
is by plane surfaces tipped with cartilage ; and at its lower end 
the cartilage seems to glue the two bones together; not, how- 
ever, so firmly in young people, but that the motion at the other 
end is very observable. In old subjects, the two bones of the 
leg are sometimes united by anchylosis at their lower ends. 

The principal use of this bone is to afford origin and insertion 
to muscles ; and to give a particular direction to their tendons. 
It likewise assists to make the articulation of the foot more se- 
cure and firm, and to complete the hinge-like joint at the ankle. 
The ends of the tibia and fibula being larger than their middle, 
a space is here left, which is filled up with a ligament similar to that 
which is extended between the bones of the forearm ; and which 
is also discontinued at its upper part, where the tibialis anticus 
immediately adheres to the solseus and tibialis posticus; but 
every where else it gives origin to muscular fibres. 

The Patella or Rotula 

Is a small flat bone situated at the forepart of the joint of the 
knee. Its shape resembles the common figure of the heart with 
its point downwards. The anterior convex surface of the rotula 
is pierced by a great number of holes, into which are inserted 
the fibres of the strong ligament that is spread over it. Its poste- 
rior surface is smooth, covered with cartilage, and divided by a 
middle convex ridge into two cavities, of which the external is 
largest ; and both are exactly adapted to the pulley of the os 
femoris, on which they are placed in the most ordinary unstrain- 
ing postures of the legs : but, when the leg is much bent, the pa- 
tella descends far down on the condyles; and when the leg is fully 
extended, the patella rises higher in its upper part than the pul- 
ley of the thigh bone. The plane smooth surface is surrounded 
by a rough prominent edge, to which the capsular ligament 
adheres. Below, the point of the bone is scabrous, where the 
strong tendinous ligament from the tubercle of the tibia is fixed. 
The upper horizontal part of this bone is flattened and une- 
qual where the tendons of the extensors of the leg are inserted. 

The substance of the patella is cellular, with very thin firm ex-. 

16* 



186 



PATELLA. 



ternal plates ; but then these cells are so small and such a quan- 
tity of bone is employed in their formation, that scarce any 
bone of its bulk is so strong. But, notwithstanding this strength, 
it is sometimes broken by the violent straining effort of the mus- 
cles. 

The principal motions of the knee joint are flexion and extension. 
In the former of these, the leg may be brought to a very acute angle 
with the thigh, by the condyles of the thigh bones being round, 
and made smooth far backwards. In performing this, the patella 
is pulled down by the tibia. When the leg is to be extended, the 
patella is drawn upwards, consequently, the tibia forwards, by 
the extensor muscles; which, by means of the protuberant joint, 
and of this thick bone with its ligament, have the chord, with 
which they act, fixed to the tibia at a considerable angle, and 
act, on that account, with advantage ; but they are restrained 
from pulling the leg farther than to a straight line with the thigh, 
by the posterior part of the cross ligament, that the body might 
be supported by a firm perpendicular column : for, at this time, 
the thigh and leg are as little movable in a rotary way, or to 
either side, as if they were one continued bone. But, when the 
joint is a little bent, the rotula is not tightly braced, and the pos- 
terior ligament is relaxed ; therefore, this bone may be moved a 
little to either side, or with a small rotation in the superficial 
cavities of the tibia ; which is done by the motion of the exter- 
nal cavity backwards and forwards, the internal serving as a 
sort of axis. Seeing, then, one part of the cross ligament is 
situated perpendicularly, and the posterior part is stretched ob- 
liquely from the internal condyle of the thigh outwards, that pos- 
terior part of the cross ligament prevents the leg from being 
turned much inwards ; but it could not hinder it from turning 
outwards almost round, were not that motion confined by the 
lateral ligaments of this joint, which can yield little. 

This rotation of the leg outwards is of great advantage to us 
in crossing our legs, and turning our feet outwards, on several 
necessary occasions; though it is necessary that this motion should 
not be very large, to prevent frequent luxations here. While 
all these motions are performing, the part of the tibia that moves 



THE FOOT— TARSUS. 



187 



immediately on the condyles is that which is within the cartila- 
ginous rings, which, by the thickness on their outsides, make the 
cavities of the tibia more horizontal, by raising their external 
side where the surface of the tibia slants downwards. By these 
means the motions of this joint are more equal and steady than 
otherwise they would have been. The cartilages being capable 
of changing a little their situation, contribute to the different mo- 
tions and postures of the limb, and, likewise, make the motions 
larger and quicker. 

The Foot. 

The foot is divided into the tarsus, metatarsus, and toes. 
The sole of the foot is necessarily described as the inferior 
part, and the side of the great toe as the internal. 

Tarsus. 

The tarsus consists of seven spongy bones ; to wit, the astra- 
galus, os calcis, naviculare, cuboides, cuneiforme externum, cunei- 
forme medium, and cuneiforme internum. 

The astragalus is the uppermost of these bones. The os calcis 
is below the astragalus, and forms the heel. The os naviculare 
is in the middle of the internal sides of the tarsus. The os cu- 
boides is the most external of the row of four bones, at its fore- 
part. The 05 cuneiforme externum is placed at the inside of the 
cuboid. The cuneiforme medium is between the external and 
internal cuneiforme bones ; and the internal cuneiforme is at the 
internal side of the foot. 

The upper part of the astragalus is formed into a large smooth 
head, which is slightly hollowed in the middle ; and therefore 
resembles a superficial pulley, by which it is fitted to the lower 
end of the tibia. The internal side of this head is flat and 
smooth, to play on the internal malleolus. The external side 
has also such a surface, but larger, for its articulation with the 
external malleolus. Round the base of this head there is a rough 
fossa ; and immediately before the head, as also below its in- 
ternal smooth surface, we find a considerable rough cavity. 

The lower surface of the astragalus is divided by an irregular 



ASTRAGALUS. 



deep rough fossa, which, at its internal end, is narrow, but gra- 
dually widens as it stretches obliquely outwards and forwards. 
The smooth surface, covered with cartilage, behind this fossa, 
is large, oblong, extended in the same oblique situation with the 
fossa, and concave for its conjunction with the os calcis. The 
posterior edge of this cavity is formed by two sharp-pointed 
rough processes, between which is a depression made by the 
tendon of the flexor pollicis longus. The lower surface before 
the fossa is convex, and composed of three distinct smooth 
planes. The long one behind, and the exterior or shortest, are 
articulated with the heel bone; while the internal, which is the 
most convex of the three, rests and moves upon a cartilaginous 
ligament, that is continued from the os calcis to the os navicu- 
lar, without which ligament the astragalus could not be sus- 
tained, but would be pressed out of its place by the great weight 
it supports; and the other bones of the tarsus would be separated. 
Nor would a bone be fit here, because it must have been thicker 
than could conveniently be allowed ; otherwise it would break, 
and would not prove such an easy bending base, to lessen the 
shock which is given to the body, in leaping, running, &c. 

The forepart of this bone is formed into a convex oblong 
smooth head, which is received by the os naviculare, and is 
placed obliquely ; its longest axis inclining downwards and in- 
wards. Round the root of this head, especially on the upper 
surface, a rough fossa may be remarked. 

The astragalus is articulated above to the tibia and fibula, 
which together form one cavity. In this articulation, flexion 
and extension are the most considerable motions; the other mo- 
tions being restrained by the malleoli, and by the strong liga- 
ments which go out from the points of these processes, to the 
astragalus and os calcis. When the root is bent, as it commonly 
is when we stand, no lateral or rotary motion is allowed in this 
joint; for then the head of the astragalus is sunk deep between 
the malleoli, and the ligaments are tense: but when the foot is 
extended, the astragalus can move a little to either side, and 
with a small rotation. By this contrivance, the foot is firm, 
when the weight of the body is to be supported on it ; and, when 



OS C ALOIS. Igg 

a foot is raised, we are at liberty to direct it more exactly to 
the place we intend next to step upon. 

The astragalus is joined below to the os calcis; and before to 
the os naviculare, in the manner to be explained when these 
bones are described. 

The os calcis is the largest bone of the seven. Behind, it is 
formed into a large knob, commonly called the heel, the poste- 
rior surface of which is rough below for the insertion of what 
is called the tendo-achillis, and oblique above to allow the heel 
to be depressed without pressing against the tendon. On the 
upper surface of the os calcis, there is an irregular oblong 
smooth convexity, adapted to the concavity at the back part of 
the astragalus; and beyond this a narrow fossa is seen, which 
divides it from two small concave smooth surfaces, that are 
joined to the forepart of the astragalus. The posterior of these 
smooth surfaces, which is the largest, is the upper surface of a 
process which projects inwards: and under it is a small sinuosity 
for the tendon of the flexor digitorum longus. 

The external side of this bone is flat, with a superficial fossa 
running horizontally, in which the tendon of the musculus pero- 
nseus longus is lodged. The internal side of the heel bone is 
hollowed, for lodging the origin of the massa carnea, and for 
the safe passage of tendons, nerves, and arteries. Under the 
side of the internal smooth concavity, a particular groove is 
made by the tendon of the flexor pollicis longus; and from the 
thin protuberance of this internal side a cartilaginous ligament 
that supports the astragalus, goes out to the os naviculare ; on 
which ligament, and on the edge of this bone to which it is fixed, 
the groove is formed for the tendon of the flexor digitorum pro- 
fundus. 

The lower surface of this bone is flat at the back part, and 
immediately before this plane, there are two tubercles, from the 
internal of which the musculus abductor pollicis, flexor digitorum 
sublimis, as also part of the aponeurosis plantaris, and of the ab- 
ductor minimi digiti, have their origin ; and the other part of the 
abductor minimi digiti and aponeurosis plantaris rises from the 
external. Before these protuberances, this bone is concave, for 



IQQ OS CUBOIDES. 

lodging the flexor muscles ; and, at its forepart, we may observe 
a rough depression, from which, and a tubercle behind it, the 
ligament goes out that prevents this bone from being separated 
from the os cuboides. 

The forepart of the os calcis is formed into an oblong pulley- 
like smooth surface, which is circular at its upper externa] end, 
but is pointed below. The smooth surface is fitted to the os 
cuboides. 

Though the surfaces by which the astragalus and os calcis are 
articulated, seem fit enough for motion, yet the very strong liga- 
ments, by which these bones are connected, prevent much mo- 
tion, and give firmness to this principal part of our base, which 
rests on the ground. 

Os naviculare is somewhat oval. It is formed into an oblong 
concavity behind, for receiving the anterior head of the astraga- 
lus. The upper surface is convex. Below, the surface is very 
unequal and rough ; but hollow for the safety of the muscles. 
Its internal extremity is very prominent. The abductor pollicis 
takes in part its origin from it, the tendon of the tibialis posticus 
is inserted into it, and to it two remarkable ligaments are fixed; 
the first is the strong one, formerly mentioned, which supports 
the astragalus; the second is stretched from this bone obliquely 
across the foot, to the metatarsal bones of the middle toe, and 
of the toe next to the little one. On the outside of the os navi- 
culare there is a semicircular smooth surface, where it is joined 
to the os cuboides. The forepart of this bone is covered with 
cartilage, and divided into three smooth planes, fitted to the 
three ossa cuneiformia. 

The os naviculare and astragalus are joined as a ball and 
socket ; and the naviculare moves in several directions in turn- 
ing the toes inwards, or in raising or depressing either side of 
the foot, though the motions are greatly restrained by the liga- 
ments which connect this to the other bones of the tarsus. 

Os cuboides is an irregular cube. Behind, it is formed into an 
oblong unequal cavity, adapted to the forepart of the os calcis. 
On its internal side, there is a small semicircular smooth cavity, 
to join the os naviculare. Immediately before which, an oblong 



OS CUNEIFORME. jqj 

smooth plane is made by the os cuneiforme externum ; below 
this the bone is hollow and rough. On the internal side of the 
lower surface, a round protuberance and fossa are found, where 
the musculus adductor pollicis has its origin. On the external 
side of this surface, there is a broad ridge running forwards and 
inwards, covered with cartilage; immediately before which a 
smooth fossa may be observed, in which the tendon of the 
peronEeus primus runs obliquely across the foot. Before, the 
surface of the os cuboides is flat, smooth, and slightly divided 
into two planes, for sustaining the os metatarsi of the little toe, 
and of the toe next to it. 

The form of the back part of the os cuboides, and the liga- 
ments connecting the joint with the os calcis, both concur in 
allowing little motion in this part. 

Os cuneiforme externum is shaped like a wedge, being broad 
and flat above, with long sides running obliquely downwards, 
and terminating in an edge. The upper surface of this bone is 
an oblong square. The one behind is nearly a triangle, but not 
complete at the inferior angle, and is joined to the os naviculare. 
The external side is an oblong square divided as it were by a 
diagonal; the upper half of it is smooth, for its conjunction with 
the os cuboides : the other is a scabrous hollow, with a small 
smooth impression made by the os metatarsi of the toe next to 
the little one. The internal side of this bone is flattened before 
by the metatarsal bone of the toe next to the great one, and the 
back part is also flat and smooth where the os cuneiforme medium 
is contiguous to it. The forepart of this bone is triangular, for 
sustaining the os metatarsi of the middle toe. 

Os cuneiforme, or minimum, is still more exactly the shape of 
a wedge than the former. Its upper part is square ; its internal 
side has a flat smooth surface for its connexion with the adjoin- 
ing bone; the external side is smooth and a little hollowed, 
where it is contiguous to the last described bone. Behind, this 
bone is triangular, where it is articulated with the os naviculare; 
and it is also triangular at its forepart, where it is contiguous to 
the os metatarsi of the toe next to the great one. 

The broad thick part of the os cuneiforme maximum, or in- 



j g2 METATARSUS. 

ternum, is placed below, and the small thinner edge is above. 
The surface of the os cuneiforme behind, where it is joined to 
the os naviculare, is hollow, smooth, and of a circular figure be- 
low, but pointed above. The external side consists of two 
smooth and flat surfaces. With the posterior, that runs ob- 
liquely forwards and outwards, the os cuneiforme minimum is 
joined ; and with the anterior, whose direction is longitudinal, 
the os metatarsi of the toe next to the great one is connected. 
The forepart of this bone is flat and smooth, for sustaining the 
os metatarsi of the great toe. The internal side is scabrous, 
with two remarkable tubercles below, from which the musculus 
abductor pollicis rises, and the tibialis anticus is inserted into its 
upper part. 

The three cuneiforme bones are all so secured by ligaments, 
that very little motion is allowed in any of them. 

These seven bones of the tarsus, when joined, are convex 
above, and leave a concavity below, for lodging safely the seve- 
ral muscles, tendons, vessels, and nerves, that lie in the sole of 
the foot. In the recent subject, their upper and lower surfaces 
are covered with strong ligaments, which adhere firmly to them; 
and all the bones are so tightly connected by these and the other 
ligaments, which are fixed to the rough ridges and fossae, that 
notwithstanding the many surfaces covered with cartilage, some 
of which are of the form of the very movable articulations, no 
more motion is here allowed, than is necessary to prevent too 
great a shock of the fabric of the body in walking, leaping, &c. 
by falling on too solid a base. If the tarsus was one continued 
bone, it would likewise be much more liable to be broken, and 
the foot could not accommodate itself to the surfaces we tread 
on by becoming more or less hollow, or by raising or depressing 
either of its sides. 

Metatarsus. 

The Metatarsus is composed of five bones, which agree, in 
their general characters, with the metacarpal bones ; but may be 
distinguished from them by the following marks: 1. They are 
longer, thicker, and stronger. 2. Their anterior round ends are 



METATARSUS. 



193 



not so broad, and are less in proportion to their bases. 3. Then- 
bodies are sharper above and flatter on their sides, with their in- 
ferior ridge inclined more to the outside. 4. The tubercles at 
the lower part of the round head are larger. 

The first or internal metatarsal bone is easily distinguished 
from the rest by its thickness. The one next to it is the longest, 
and with its sharp edge almost perpendicular. The others are 
shorter and more oblique, as their situation is more external. 
Which general remarks, with the description now to be given of 
each, may teach us to distinguish them from each other. 

Os metatarsi pollicis is by far the thickest and strongest, as 
having much the greatest weight to sustain. Its base is oblong, 
irregularly concave, and of a semilunar figure, to be adapted to 
the os cuneiforme maximum. The inferior edge of this base is 
a little prominent and rough, where the tendon of the peronaeus 
primus muscle is inserted. On its outside, an oblique circular 
depression is made by the second metatarsal bone. Its round 
head has generally on its forepart a middle ridge, and two ob- 
long cavities, for the ossa sesamoidea ; and, on the external side, 
a depression is made by the following bone. 

Os metatarsi of the second toe is the longest of the five, with a 
triangular base supported by the os cuneiforme medium, and the 
external side produced into a process ; the end of which is an 
oblique smooth plane, joined to the os cuneiforme externum. 
Near the internal edge of the base, this bone has two small de- 
pressions, made by the os cuneiforme maximum, between which 
is a rough cavity. Farther forwards we may observe a smooth 
protuberance, which is joined to a foregoing bone. On the out- 
side of the base are two oblong smooth surfaces for its articula- 
tion with the following bone; the superior smooth surface being 
extended longitudinally, and the inferior perpendicularly, be- 
tween which there is a rough fossa. 

Os metatarsi of the middle toe is the second in length. Its 
base, supported by the os cuneiforme externum, is triangular, but 
slanting outwards, where it ends in a sharp-pointed little process, 
and the angle below it is not completed. 

The internal side of this base is best adapted to the preceding 
vol. i. 17 



194 



THE TOES. 



bone ; and the external side has also two smooth surfaces covered 
with cartilage, but of a different figure ; for the upper one is 
concave, and being round behind, turns smaller as it advances 
forwards; and the lower surface is a little smooth, convex, and 
very near the edge of the base. 

Os metatarsi of the fourth toe is nearly as long as the former, 
with a triangular slanting base joined to the os cuboides, and 
made round at its external angle ; having one hollow smooth 
surface on the outside, where it is pressed upon by the following 
bone ; and two on the internal side, corresponding to the former 
bone, behind which is a long narrow surface impressed by the 
os cuneiforme externum. 

Os metatarsi of the little toe is the shortest, situated with its 
two flat sides above and below, and with the ridges laterally. 
The base of it, part of which rests on the os cuboides, is very 
large, tuberous, and produced into a long-pointed process ex- 
ternally, where part of the abductor minimi digiti is fixed ; and 
into its upper part the peronseus secundus is inserted. Its inside 
has a flat conoidal surface, where it is contiguous to the pre- 
ceding bone. 

When we stand the fore ends of these metatarsal bones, and 
the os calcis, are our only supporters, and, therefore, it is neces- 
sary that they should be strong, and should have a confined mo- 
tion. 

The Toes. 

The bones of the toes are nearly similar to those of the thumb 
and fingers; particularly the two of the great toe, which are 
precisely formed as the two last of the thumb; but their position, 
as respects the other toes, is not oblique ; and they are propor- 
tionally much stronger, because they are subjected to a greater 
force ; for they sustain the force by which our bodies are pushed 
forwards by the foot behind at every step we make; and on them 
principally the weight of the body is supported, when we are 
raised on our tip-toes. 

The three bones in each of the other four toes, compared 
with those of the fingers, differ from them in these particulars. 



STRUCTURE OF THE FOOT. J95 

They are less, and smaller in proportion to their lengths. Their 
bases are much larger than their anterior ends. The first pha- 
lanx is proportionally much longer than the bones of the second 
and third, which are very short. 

The toe next to the great one has the largest bones in all di- 
mensions, and the bones of the other toes diminish according to 
the order of their position ; those of the exterior being least. 

The general Structure of the Foot. 

The foot may be considered as an arch, of which the back 
part of the heel, and the anterior extremities of the metatarsal 
bones and the toes, are the abutments. The heel, or posterior 
abutment, is not so broad as the anterior, and is placed on the 
outside and not in the middle of the extremity of the arch. The 
process on the inside of the os calcis, which supports the astra- 
galus, increases the breadth of the arch ; and the os naviculare 
completes it. The arch, thus constructed, does not appear very 
firm, and this apparent want of strength seems increased by the 
position of the anterior portion of the astragalus, a part of which 
is between the os calcis and os naviculare, and not supported by 
either. These bones, however, are firmly connected by liga- 
ments, and one which passes from the os calcis to the os navicu- 
lare, under the forepart of the astragalus, gives effectual support 
to that bone. 

The outside of the foot, formed by the os calcis, os cuboides, 
and the lesser metatarsal bone, does not partake much of the 
nature of an arch; for it is almost flat. As the internal side forms 
a considerable arch, the foot is to be considered as possessing a 
double convexity, viz. transversely, as well as longitudinally. 

The great toe, from its internal situation, is the principal ante- 
rior abutment of the arch on the internal side of the foot ; hence 
its great importance. 

The astragalus, which is the basis of the tibia, and of course 
pressed by half of the weight of the body when we stand, appears 
to be in a situation which is very oblique, and imperfectly sup- 
ported; and accordingly it has been completely forced from its 
position, by accidents in which the leg has been twisted or turned 



19G SESAMOID BONES-EXTREMITIES OF THE FCETUS. 

inward, and the foot prevented from turning with it. It is pro- 
bable that this misfortune would often take place if the fibula did 
not previously yield, as in some of the cases of fracture of that 
bone near the external ankle. 

One great object of this peculiar structure is, that the foot may 
yield in cases of violent and sudden pressure, as when we jump 
or fall upon the feet. The safety of the foot, and the facility of 
its ordinary movement, are not the only objects of its peculiar 
structure, but concussion of the whole body, and particularly of 
the brain, is thereby avoided to a certain degree. 

This may be inferred from the fact that many persons suffer 
violent concussions, in consequence of falling upon other parts of 
the body, who are free from these effects when they fall upon the 
feet. 

The Sesamoid Bones 

Are seldom larger than half a pea. They are most commonly 
found at the second joint of the thumb, and of the great toe; and 
are placed in pairs, especially at the great toe, between the 
tendons of the flexor muscles and the bones. In these situations 
they are convex externally, and on their internal surfaces they are 
concave and covered with cartilage. 

They are also sometimes found between the heads of the 
gastrocnemius muscle and the condyles of the os femoris. 

In the joints of the thumb and toe they appear to be very 
analogous to the patella. 

The Extremities of the Foetus. 

In the upper extremity the clavicle is almost perfect at birth ; 
but the acromion and coronoid processes of the scapula, as well 
as the head, are in a cartilaginous state. 

Both ends of the os humeri are cartilaginous. They after- 
wards ossify in the form of epiphyses, and are united to the body 
of the bone. 

The two bones of the forearm are in the same situation. 

There are no bones of the carpus; but in their situation is an 
equal number of cartilages, which resemble them exactly. These 



EXTREMITIES OF THE FCETUS 



197 



cartilages are separated from each other, by synovial membranes, 
as the bones afterwards are. Each of them ossifies from a single 
point, except the unciforme. 

The metacarpal bones, and the first bone of the thumb, have 
cartilages at each extremity, which afterwards become epiphyses. 

The bones of the phalanges are likewise cartilaginous at each 
extremity. The extremities next to the hand are epiphyses; but 
it is probable that the other extremities ossify gradually from 
their centres.* 

In the lower extremity, the head and neck, and two trochanters 
of the os femoris are cartilaginous and form three epiphyses. 

The other end of this bone is also cartilaginous, and constitutes 
but one epiphysis, notwithstanding its size ; the ossification com- 
mencing in the centre. 

At birth, the body of the os femoris is less curved than it 
becomes afterwards; and the angle formed by the neck of the 
bone is less obtuse than in the adult. 

The patella is entirely cartilaginous at birth. 

The two extremities of the tibia and fibula are also cartilagi- 
nous, and become epiphyses. 

The astragalus and os calcis are somewhat ossified within, and 
have a large portion of cartilage exteriorly. 

In place of the other bones of the tarsus there are cartilages 
of their precise shape, which are as distinct from each other as 
the future bones are. 

The state of the metatarsal bones, and the phalanges of the 
toes, resembles that of the bones of the hand.f 

* See Nesbit's Osteology, page 126. 

t Volehn Koyter, a disciple of Fallopius, has given to the profession one of the 
best accounts of Osteogeny, according to Lassus. — h. 

17* 



199 



ANATOMICAL PLATES. 



EXPLANATION OF THE PLATES OF OSTEOLOGY. 

Plate II. 

Fig. 1. A Front View of the Male Skeleton. 

A, The os frontis. B, The os parietale. C, The coronal suture. D, 
The squamous part of the temporal bones. E, The squamous suture. F, 
The zygoma. G, The mastoid process. H, The temporal process of the 
sphenoid bone. I, The orbit. K, The os malse. L, The os maxillare su- 
perius. M, Its nasal process. N. The ossa nasi. O, The os unguis. P, 
The maxilla inferior. Q, The teeth, which are sixteen in number in each 
jaw. R, The seven cervical vertebrae, with their intermediate cartilages. 
S, Their transverse processes. T, The twelve dorsal vertebra?, with their 
intermediate cartilages. U, The five lumbar vertebrae. V, Their trans- 
verse process. W, The upper part of the os sacrum. X, Its lateral parts. 
The holes seen on its forepart are the passages of the undermost spinal 
nerves and small vessels. Opposite to the holes, the marks of the original 
division of the bones are seen. Y, The os ilium. Z, Its crest or spine, a, 
The interior spinous processes, b, The brim of the pelvis, c, The ischi- 
atic notch, d, The os ischium, e, Its tuberosity, f, Its spinous process, 
g, Its crus. h, The foramen thyroideum. i, The os pubis, k, The sym- 
physis pubis. 1, The crus pubis, m, The acetabulum, n, The seventh or 
last true rib. o, The twelfth or last false rib. p, The upper end of the 
sternum, q, The middle piece, r, The upper end, or cartilago ensiformis. 
s, The clavicle, t, The internal surface of the scapula, u, Its acromion, 
v, Its coracoid process, w, Its cervix, x, The glenoid cavity, y, The os 
humeri, z, Its head, which is connected to the glenoid cavity. 1, Its in- 
ternal tubercle. 2, Its external tubercle. 3, The groove for lodging the 
long head of the biceps muscle of the arm. 4, The internal condyle. Be- 
tween 4 and 5, the trochlea. 6, The radius. 7, Its head. 8, Its tubercle. 
9, The ulna. 10, Its coronoid process. 11, 12, 13, 14, 15, 16, 17, 18, 
The carpus, composed of the os naviculare, os lunare, os cuneiforme, os pisi- 
forme, os trapezium, os trapezoides, os magnum, os unciforme. 19, The five 
bones of the metacarpus. 20, The two bones of the thumb. 21, The three 
bones of each of the fingers. 22, The os femoris. 23, Its head. 24, Its 
cervix. 25, The trochanter major. 26, Trochanter minor. 27, The in- 
ternal condyle. 28, The external condyle. 29, The rotula. 30, The ti- 
bia. 31, Its head. 32, Its tubercle. 33, Its spine. 34, The malleolus in- 
ternus. 35, The fibula. 36, Its head. 37, The malleolus externus. The 
tarsus is composed of, 38, The astragalus; 39, The os calcis ; 40, The os 
naviculare ; 41, Three ossa, cuneiformia, and the os cuboides, which is not 



200 EXPLANATION OF THE PLATES OF OSTEOLOGY. 

seen in this figure. 42, The five bones of the metatarsus. 43, The two 
bones of the great toe. 44, The three bones of each of the small toes. 

Fig. 2. A Front View of the Skull. 

A, The os frontis. B, The lateral part of the os frontis, which gives 
origin to part of the temporal muscle. C, The superciliary ridge. D, 
The superciliary hole through which the frontal vessels and nerves pass. 
E E, The orbitar processes. F, The middle of the transverse suture. G, 
The upper part of the orbit. H, The foramen opticum. I, The foramen 
lacerum. K, The inferior orbitar fissure. L, The os unguis. M, The ossa 
nasi. N, The os maxillare superius. O, Its nasal process. P, The ex- 
ternal orbitar hole through which the superior maxillary vessels and nerves 
pass. Q. The os malae. R, A passage for small vessels into or out of the 
orbit. S, The under part of the left nostril. T, The septum narium. U, 
The os spongiosum superius. V, The os spongiosum inferius. W, The 
edge of the alveoli, or spongy sockets for the teeth. X, The maxilla infe- 
rior. Y, The passage for the inferior maxillary vessels and nerves. 

Fig. 3. A Side View of the Skull. 

A, The os frontis. B, The coronal suture. C, The os parietale. D, An 
arched ridge, which gives origin to the temporal muscle. E, The squamous 
suture. F, The squamous part of the temporal bone ; and farther forwards, 
the temporal process of the sphenoid bone. G, The zygomatic process of 
the temporal bone. H, The zygomatic suture. I, The mastoid process of 
the temporal bone. K, The meatus auditorius externus. L, The orbitar 
plate of the frontal bone, under which is seen the transverse suture. M, 
The pars plana of the ethmoid bone. N, The os unguis. O, The right os 
nasi. P, The superior maxillary bone. Q, Its nasal process. R, The two 
dentes incisores. S, The dens caninus. T, The two small molares. U, 
The three large molares. V, The os malse. W, The lower jaw. X, Its 
angle. Y, The coronoid process. Z, The condyloid process by which the 
jaw is articulated with the temporal bone. 

Fig. 4. The Posterior and Right Side of the Skull. 

A, The os frontis. BB, The ossa parietalia. C, The sagittal suture. 
D, The parietal hole, through which a small vein runs to the superior longi- 
tudinal sinus. E, Thelambdoid suture. FF, Ossa triquetra. G, The os 
occipitis. H, The squamous part of the temporal bone. I, The mastoid 
process. K, The zygoma. L, The os malse. M, The temporal part of the 
sphenoid bone. N, The superior maxillary bone and teeth. 

Fig. 5. The External Surface of the Os Frontis. 

A, The convex part. B, Part of the temporal fossa. C, The external 
angular process. D, The internal angular process. E, The nasal process. 
F, The superciliary arch. G, The superciliary hole. H, The orbitar plate. 

Fig. 6. The Internal Surface of the Os Frontis. 

A A, The serrated edge which assists to form the coronal suture. B, The 
external angular process. C, The internal angular process. D, The nasal 
process. E, The orbitar plate. F, The cells which correspond with those 



$*? 




- y • - 

K - 



EXPLANATION OF THE PLATES OF OSTEOLOGY. 



201 



of the ethmoid bone. G, The passage from the frontal sinus. H, The 
opening which receives the cribriform plate of the ethmoid bone. I, The 
cavity which lodges the forepart of the brain. K, The spine to which the 
falx is fixed. L, The groove which lodges the superior longitudinal sinus. 

Plate III. 
Fig. 1. A Back View of the Skeleton. 

A A, The ossa parietalia. B, The sagittal suture. C, The lambdoid su- 
ture. D, The occipital bone. E, The squamous suture. F, The mastoid 
process of the temporal bone. G, The os malte. H, The palate plates of 
the superior maxillary bone. I, The maxilla inferior. K, The teeth of 
both jaws. L, The seven cervical vertebrae. M, Their spinous processes. 
N, Their transverse and oblique processes. O, The last of the twelve dor- 
sal vertebree. P, The fifth or last lumbar vertebra?. Q, The transverse 
processes. R, The oblique processes. S, The spinous process. T, The 
upper part of the os sacrum. U, The posterior holes which transmit small 
blood-vessels and nerves. V, The under part of the os sacrum which is co- 
vered by a membrane. W, The os coccygis. X, The os ilium. Y, Its 
spine or crest. Z, The ischiatic notch, a, The os ischium, b, Its tube- 
rosity, c, Its spine, d, The os pubis, e, The foramen thyroideum. f, The 
seventh or last true rib. g, The twelfth or last false rib. h, The clavicle, 
i, The scapula, k, Its spine. 1, Its acromion, m, Its cervix, n, Its su- 
perior costa. o, Its posterior costa. p, Its inferior costa. q, The os hu- 
meri, r, The radius, s, The ulna, t, Its olecranon, u, All the bones of 
the carpus, excepting the os pisifbrme, which is seen in Plate II. Fig. 1. v, 
The five bones of the metacarpus, w, The two bones of the thumb, x, 
The three bones of each of the fingers, y, The two sesamoid bones of the 
root of the left thumb, z, The os femoris. 1, The trochanter major. 2, 
The trochanter minor. 3, The linea aspera. 4, The internal condyle. 5, 
The external condyle. 6 6, The semilunar cartilages. 7, The tibia. 8, 
The malleolus internus. 9, The fibula. 10, The malleolus externus. 11, 
The tarsus. 12, The metatarsus. 13, The toes. 

Fig. 2. The External Surface of the left Os Parietale. 

A, The convex smooth surface. B, The parietal hole. C, An arch made 
by the beginning of the temporal muscle. 

Fig. 3. The Internal Surface of the same Bone. 

A, Its superior edge, which, joined with the other, forms the sagittal su- 
ture. B, The anterior edge, which assists in the formation of the coronal su- 
ture. C, The inferior edge for the squamous suture. D, The posterior 
edge for the lambdoid suture. E, A depression made by the lateral sinus. 
F, The prints of the arteries of the dura mater. 

Fig. 4. The External Surface of the left Os Temporis. 

A, The squamous part. B, The mastoid process. C, The zygomatic 
process. D, The styloid process. E, The petrosal process. F, The mea- 
tus auditorius externus. G, The glenoid cavity for the articulation of the 
lower jaw. H, The foramen stylo-mastoideum for the portio dura of the 
seventh pair of nerves. I, Passages for blood-vessels into the bone. K, 
The foramen mastoideum, through which a vein goes to the lateral sinus. 



•^()2 EXPLANATION OF THE PLATES OF OSTEOLOGY. 

Fig. 5. The Internal Surface of the left Os Temporis. 

A, The squamous part, the upper edge of which assists in forming the 
squamous suture. B, The mastoid process. C, The styloid process. D, 
The pars petrosa. E, The entry of the seventh pair, or auditory nerve. 
F, The fossa, which lodges a part of the lateral sinus. G, The foramen 
mastoideum. 

Fig. 6. The External Surface of the Osseous Circle, which terminates 
the Meatus Auditorius Externus. 

A, the anterior part. B, A small part of the groove in which the mem- 
hrana tympani is fixed. 

N. B. This, with the subsequent bones of the ear, are here delineated as 
large as the life. 

Fig. 7. The Internal Surface of the Osseous Circle. 

A, the anterior part. B, the groove in which the membrana tympani is 
rlxed. 

Fig. 8. The Situation and Connexion of the Small Bones of the Ear. 
A, The malleus. B, The incus. C, the os orbiculare. D, The stapes. 

Fig. 9. The Malleus, with its Head, Handle, and Small Processes. 

Fig. 10. The Incus, with its Body, Superior and Inferior Branches. 

Fig. 11. The Os Orbiculare. 

Fig. 12. The Stapes, with its Head, Base, and two Crura. 

Fig. 13. An Internal View of the Labyrinth of the Ear. 

A, The hollow part of the cochlea, which forms a share of the meatus au- 
ditorius internus. B, The vestibulum. C C C, The semicircular canals. 

Fig. 14. An External View of the Labyrinth. 

A, the semicircular canals. B, The fenestra ovalis, which leads into the 
vestibulum. C, The fenestra rotunda which opens into the cochlea. D, 
The different turns of the cochlea. 

Fig. 15. The Internal Surface of the Os Sphenoides. 

A A, The temporal processes. B B, The pterygoid processes. C C, The 
spinous processes. D D, The anterior clinoid processes. E, The posterior 
clinoid process. F, The anterior process which joins the ethmoid bone. G, 
The sella turcica for lodging the glandula pituitaria. H, The foramen op- 
ticum. K. The foramen lacerum. L, The foramen rotundum. M, The 
foramen ovale. N, The foramen spinale. 

Fig. 16. The External Surface of the Os Sphenoides. 

A A, The temporal processes. B B, The pterygoid processes. C C. The 
spinous processes. D, The processus azygos. E, The small triangular pro- 







• I • 



EXPLANATION OF THE PLATES OF OSTEOLOGY. 203 

cesses which grow from the body of the bone. F F, The orifices of the sphe- 
noid sinuses. G, The foramen lacerum. H, The foramen rotundum. I, 
The foramen ovale. K, The foramen pterygoideum. 

Fio. 17. The External View of the Os Ethmoides. 

A, The nasal lamella. B B, The grooves between the nasal lamella and 
ossa spongiosa snperiora. CC, The ossa spongiosa superiora. DD, The 
sphenoidal cornua. See Fig. 16, E. 

Fig. 18. The Internal View of the Os Ethmoides. 

A, The crista galli. B, The cribriform plate, with the different passages 
of the olfactory nerves. C C, Some of the ethmoidal cells. D, The right 
os planum. EE, The sphenoidal cornua. 

Fio. 19. The right Sphenoidal Cornu. 

Fig. 20. The left Sphenoidal Cornu. 

Fig. 21. The External Surface of the Os Occipitis. 

A, The upper part of the bone. B, The superior arched ridge. C, The 
inferior arched ridge. Under the arches are prints made by the muscles of 
the neck. DD, The two condyloid processes which articulate the head 
with the spine. E, The cuneiforme process. F, The foramen magnum 
through which the spinal marrow passes. G G, The posterior condyloid fora- 
mina which transmit veins into the lateral sinuses. H H, The foramina lin- 
gualia for the passage of the ninth pair of nerves. 

Fig. 22. The Internal Surface of the Os Occipitis. 

A A, The two sides which assist to form the lambdoid suture. B, The 
point of the cuneiforme process, where it joins the sphenoid bone. C C, The 
prints made by the posterior lobes of the brain. D D, Prints made by the 
lobes of the cerebellum. E, The cruciforme ridge for the attachment of 
the process of the dura mater. F, The course of the superior longitudinal 
sinuses. GG, The course of the two lateral sinuses. H, The foramen 
magnum. 1 1, The posterior condyloid foramina. 

Plate IV. 
Fig. 1. A Side View of the Skeleton. 
A A, The ossa parietalia. B, The sagittal suture. C, The os occipitis. 
D D, The lambdoid suture. E, The squamous part of the temporal bone. F, 
The' mastoid process. G, The meatus auditorius externus. H, The os 
fronti« I, The os malte. K, The os maxillare superius. L, The maxilla 
inferior M, The teeth of both jaws. N, The seventh or last cervical 
vertebra O, The spinous processes. P, Their transverse and oblique pro- 
cesses Q, The twelfth or last dorsal vertebra. R, The fifth or last lum- 
bar vertebra. S, The spinous processes. T, Openings between the ver- 
tebra for the passage of the spinal nerves. U, The under end of the os 
sacrum. V, The os coccygis. W, The os ilium. X, The anterior spinous 
processes Y, The posterior spinous processes. Z, Ischiatic notch, a, Ine 
right os ilium, b, The ossa pubis, c, The tuberosity of the left os ischium, 
d. The scapula, e, Its spine, f, The os humeri, g, The radius, h, 1 he 



204 EXPLANATION OF THE PLATES OF OSTEOLOGY. 

ulna, i, The carpus, k, The metacarpal bone of the thumb. 1, The meta- 
carpal bones of the ringers, m, The two bones of the thumb, n, The 
three bones of each of the fingers, o, The os femoris. p, Its head, q, 
The trochanter major, r, The external condyle, s, The rotula. t, The 
tibia, u, The fibula, v, The malleolus externus. w, The astragalus, x, 
The os calcis. y, The os naviculars z, The threeossa cuneiformia. 1, 
The os cuboides. 2, The five metatarsal bones. 3, The two bones of the 
great toe. 4, The three bones of each of the small toes. 

Fig. 2. A View of the Internal Surface of the Base of the Skull. 

AAA, The two tables of the skull with the diploe. B B, The orbitar 
plates of the frontal bone. C, The crista galli, with cribriform plate of the 
ethmoidal bones on each side of it, through which the first pair of nerves 
pass. D, The cuneiforme process of the occipital bone. E, The cruciforme 
ridge. F, The foramen magnum for the passage of the spinal marrow. G, 
The zygoma, made by the joining of the zygomatic processes of the os tem- 
porum and os malae. H, The pars squamosa of the os temporis. I, The 
pars mammillaris. K, The pars petrosa. L, The temporal process of the 
sphenoid bone. M M, The anterior clinoid processes. N, The posterior 
clinoid process. O, The sella turcica. P, The foramen opticum for the 
passage of the optic nerve and ocular artery of the left side. Q,, The fora- 
men lacerum, for the third, fourth, sixth, and first of the fifth pair of 
nerves and ocular vein. R, The foramen rotundum, for the second of the 
fifth pair. S, The foramen ovale, for the third of the fifth pair. T, The 
foramen spinale, for the principal artery of the dura mater. U, The entry 
of the auditory nerve. V, The passage for the lateral sinus. W, The pas- 
sage of the eighth pair of nerves. X, The passage of the ninth pair. 

Fig. 3. A View of the External Surface of the Base of the Skull. 

A, The two dentes incisores of the right side. B, The dens caninus. C, 
The two small molares. D, The three large molares. E, The foramen 
incisivum, which gives passage to small blood-vessels and nerves. F, The 
palate plates of the ossa maxillaria and palati, joined by the longitudinal and 
transverse palate sutures. G, The foramen palatinum posterius, for the pa- 
latine vessel and nerves. H, The os maxillare superius of the right side. 
I, The os mala?. K, The zygomatic process of the temporal bone. L, The 
posterior extremity of the ossa spongiosa. M, The posterior extremity of 
the vomer which forms the back part of the septum nasi. N, The ptery- 
goid process of the right side of the sphenoid bone. O O, The foramina 
ovalia. P P, The foramina spinalia. Q.Q, The passages of the internal 
carotid arteries. R, A hole between the point of each pars petrosa and 
cuneiforme process, of the occipital bone, which is filled with a ligamentous 
substance in the recent subject. S, The passage of the left lateral sinus. 
T, The posterior condyloid foramen of the left side. U, The foramen mas- 
toideum. V, The foramen magnum. W, The inferior orbitar fissure. X, 
The glenoid cavity, for the articulation of the lower jaw. Y, The squam- 
ous part of the temporal bone. Z, The mastoid process, at the inner side of 
which is a fossa for the posterior belly of the digastric muscle, a, The sty- 
loid process, b, The meatus auditorius externus. c, The left condyle of 
the occipital bone, d, The perpendicular occipital spine, e e, The inferior 
horizontal ridge of the occipital bone, f f. The superior horizontal ridge 
which is opposite to the crucial ridge where the longitudinal sinus divides to 
form the lateral sinuses, ggg, The lambdoid suture, h, The left squamous 
suture, i, The parietal bone. 



EXPLANATION OF THE PLATES OF OSTEOLOGY. 205 

Fig. 4. The Anterior Surface of the Ossa Nasi. 

A, The upper part which joins the os frontis. B, The under end, which 
joins the cartilage of the nose. C, The inner edge, where they join each 
other. 

Fig. 5. The Posterior Surface of the Ossa Nasi. 

A A, Their cavity, which forms part of the arch of the nose. B B, Their 
ridge or spine, which projects a little to be fixed to the forepart of the sep- 
tum narium. 

Fig. 6. The External Surface of the Os Maxillare Superius of the left 

side. 

A, The nasal process. B, The orbitar plate. C, The unequal surface 
which joins the os malse. D. The external orbitar hole. E, The opening 
into the nostril. F, The palate plate. G, The maxillary tuberosity. H, 
Part of the os palati. I, The two dentes incisores. K. The dens caninus. 
L, The two small dentes molares. M, The three large dentes molares. 

Fig. 7. The Internal Surface of the Os Maxillare Superius and Os 

Palati. 

A, The nasal process. B B, Eminences for the connexion of the os spon- 
giosum inferius. D, The under end of the lachrymal groove. E, The an- 
trum maxillare. F, The nasal spine, between which and B is the cavity of 
the nostril. G, The palate plate. H, The orbitar part of the os palati. I, 
The nasal plate. K, The suture which unites the maxillary and palate 
bones. The pterygoid process of the palate bone. 

Fig. 8. The External Surface of the right Os Unguis. 

A, The orbitar part. B, The lachrymal part. C, The ridge between 
them. 

Fig. 9. The Internal Surface of the right Os Unguis. 

This side of the bone has a furrow opposite to the external ridge ; all be- 
hind this is irregular, where it covers part of the ethmoidal cells. 

Fig. 10. The External Surface of the left Os Mal^. 

A, The superior orbitar process. B, The inferior orbitar process. C, The 
malar process. D, The zygomatic process. E, The orbitar plate. F, A 
passage for small vessels into or out of the orbit. 

Fig. 11. The Internal Surface of the left Os MaljE. 

A, The superior orbitar process. B, The inferior orbitar process. C, 
The malar process. D, The zygomatic process. E, The internal orbitar 
plate or process. 

Fig. 12. The External Surface of the right Os Spongiosum Inferius. 

A, The anterior part. B, The hook-like process for covering part of the 
VOL. i. 18 



206 EXPLANATION OF THE PLATES OF OSTEOLOGY. 

antrum maxillare. C, A small process which covers part of the under end 
of the lachrymal groove. D, The inferior edge turned a little outwards. 

Fig. 13. The Internal Surface of the Os Spongiosum Inferics. 

A, The anterior extremity. B, The upper edge which joins the superior 
maxillary and palate bones. 

Fig. 14. The Posterior and External Surface of the right Os Palati. 

A, The orbitar process. B, The nasal lamella. C, The pterygoid pro- 
cess. D. The palate process. 

Fig. 15. The Interior and External Surface of the right Os Palati. 

A, The orbitar process. B, An opening through which the lateral nasal 
vessels and nerves pass. C, The nasal lamella. D, The pterygoid process. 
E, The posterior edge of the palate process for the connexion of the velum 
palati. F, The inner edge by which the two ossa palati are connected. 

Fig. 16. The Right Side of the Vomer. 

A, The upper edge which joins the nasal lamella of the ethmoid bone and 
the middle cartilage of the nose. B, The inferior edge, which is connected 
to the superior maxillary and palate bones. C, The superior and posterior 
part which receives the processus azygos of the sphenoid bone. 

Fig. 17. The Maxilla Inferior. 

A, The chin. B, The base and left side. C, The angle. D, The coro- 
noid process. E, The condyloid process. F, The beginning of the inferior 
maxillary canal of the right side, for the entry of the nerves and blood-ves- 
sels. G, The termination of the left canal. H, The two dentes incisores. 
I, The dens caninus. K, the two small molares. L, The three large mo- 
lares. 

Fig. 18. The Different Classes of the Teeth. 

1, 2, A fore and back view of the two anterior dentes incisores of the 
lower jaw. 3, 4, Similar teeth of the upper jaw. 5, 6, A fore and back 
view of the dentes canini. 7, 8, The anterior dentes molares. 9, 10, 11, 
The posterior dentes molares. 12, 13, 14, 15, 16, Unusual appearances in 
the shape and size of the teeth. 

Fig. 19. The External Surface of the Os Hyoides. 
A, The body. B B, The cornua. C C, The appendices. 



PART II. 

SYNDESMOLOGY. 
CHAPTER III. 

GENERAL ANATOMY OF THE LIGAMENTOUS, FIBROUS, OR 
DESMOID TISSUE. 

Of the ligaments and membranes which connect the different parts of the body to 
each other — Of the articular cartilages — Fibro-cartilages — Synovial capsules, 
and particular articulations. 

The tendons and the strong membranes connected with them 
called aponeuroses, the fascia which bind down some of the 
muscles and afford an origin to many of their fibres, and the 
membranes which confine the tendons, appear to be composed 
of the same substance. 

— Notwithstanding some slight shades of difference which 
exist in the physical and chemical composition of these different 
parts, they are all now included with the periosteum, perichon- 
drium, dura mater, sclerotic coat of the eye, &c, under the gene- 
ral head of ligamentous, fibrous, or desmoid tissue.* This tissue 
is sometimes called, from the whiteness of its appearance, the 
albugineous tissue. It is spread very generally throughout the 
body, and is found wherever extraordinary strength and resist- 
ance is required, without elasticity or muscular contraction. It 
has been called ligamentous or desmoid, from its fastening to- 
gether the bones and cartilages, as in the ligaments proper, and 
from binding down the muscles so as to preserve the symmetry 

* The term ligament is frequently/though not with exact propriety applied to 
the duplicatures of serous membranes, which are attached to and assist in sup- 
porting different viscera, as the liver, bladder, uterus, &.C., since these doubtless do 
not belong to the fibrous or desmoid tissue. — p. 



208 FIBROUS TISSUE. 

of the limbs, in the form of fascia and aponeurosis, and from 
fastening the tendons in their grooves in the form of their theca's 
or sheaths. The term fibrous was applied to it by Bichat, (though 
its elements are dissimilar to muscular fibre,) in consequence oi its 
performing the office of bands or chords, and being composed 
essentially of firm inelastic threads, or albuminous fibres. These 
fibres crossing each other in various directions and woven dense- 
ly together, with some intervening cellular tissue, form the apo- 
neuroses, fasciae, sheaths, articular capsules, periosteum, dura 
mater, and tunica albuginea ; arranged longitudinally, they form 
the tendons of the muscles and the straight ligaments of the 
joints. The tendons, by a little dissection, may be spread out 
into a membrane, and in some parts of the body we see them 
naturally unfolding themselves to form an aponeurosis. 
— Between all these different parts there is more or less con- 
nexion. The tendons are inserted upon the bones only through the 
intermedium of the periosteum, by which they are covered. The 
aponeuroses are connected with the periosteum by the fasciae 
which they send down between the muscles. The ligaments and 
periosteum are directly continuous, and the dura mater, as it 
sends out processes around the nerves, becomes continuous with 
the periosteum that lines the foramina of the bones, through 
which the nerves pass. Bichat, considered the periosteum the 
source and centre of this system; Bonn, of Amsterdam, as well 
as Clarus, believed the aponeuroses investing the limbs to be the 
centre; — an opinion more venerable than either of these, that of 
the Arabian anatomists, fixed it in the dura mater. But, in 
truth there is no proper centre. In many parts, there is a 
fibrous tissue isolated from the rest, as the investing coat of the 
spleen and kidneys, and the fibrous portion of the pericardium. 
— The fibrous tissue in all parts of the body is continuous, at its 
surfaces and margins, with the common cellular tissue, and in 
many parts we find it, especially in the aponeuroses and fasciae, 
degenerating insensibly into it. There appears in fact to be a 
close relationship between these two tissues; in its developement 
in the foetus, it first appears as a soft, flexible, extensible, homo- 
geneous tissue, resembling much the cellular, and presents no ap- 



FIBROUS TISSUE. 209 

pearance of fibres, till near the period of birth. As life advances 
it becomes more hard, solid and yellow, and in extreme old age 
presents much rigidity, and is occasionally even converted into 
bone. When macerated in water, or imbued with fluids, as in 
scrofulous inflammation of the joints, it presents a pulpy, spongy 
appearance, in the cells of which the fluid is contained. If the 
maceration is carried only to a limited extent, the fibres will 
separate into filaments, as delicate as those of the silk worm ; 
but by prolonged maceration these filaments themselves disap- 
pear in the cellular mass. Mascagni, believed these fibres were 
lymphatics enclosed in a vascular web. Beclard, that they 
were nothing but condensed cellular tissue. Isenflam, that it 
was cellular tissue, with the walls imbued and the cells filled with 
gluten and albumen, and more or less in the advance of life with 
earthy matter ; an opinion which seems to accord with the dif- 
ferent phases which the tissue presents. Chaussier and Bichat, 
considered the fibre as primitive and peculiar, and that macera- 
tion only brought into view the cellular tissue which connected 
the fibres together. 

— However this may be, and it is a question not yet decided, in 
the form in which it presents itself to study, it differs in many 
respects from cellular tissue. It is not elastic or yielding to the 
application of sudden force as the latter; the fibres will break or 
tear up at their bony attachment, but cannot be stretched or 
strained in the proper sense of the word. But when the force 
is gradually applied, as by the accumulation of a fluid in a joint, 
they yield to receive it, by a sort of interstitial expansion or 
growth, and retract in the same gradual manner, when the dis- 
tending power is removed. Fibrous tissue contains but little 
adipose matter, and is affected only to a slight extent in ana- 
sarca. 

The Ligaments of the Joints, 

— Are all divided into the capsular or bag-like, and into funicu- 
lar, or cords. 

— The capsular, are fibrous bags, of greater or less thickness, 
open at both ends, into which the heads of the bones forming the 

18* 



210 FIBROUS TISSUE. 

respective joints are thrust, and round the necks of which it is 
closely inserted, where they are continuous with the periosteum 
of the bones. In very many of the joints the capsules are im- 
perfect in some part of their periphery, and in others are repre- 
sented only by a few scattered fibres. The hip and shoulder 
joint furnish the best specimen of a perfect capsule. 
— The funicular ligaments are cords, flat, round, or oval, in- 
tended to give a side support to the joints, and constitute the 
lateral ligaments. These are placed, some within, some without, 
and some in the very thickness of the capsular ligament. — 

They consist of fibres which are flexible but extremely strong, 
and in general have but little elasticity ; their surfaces are smooth 
and polished ; their colour is whitish and silver-like. 

The vessels which enter into their composition do not com- 
monly carry red blood ; and although it seems certain that they 
must have nerves, many very expert anatomists have declared 
that no nerves could be traced into them. 

In a healthy state, they are entirely void of sensibility, and 
can be cut and punctured, or corroded with caustic applications, 
without pain. When inflamed they are extremely painful. 

The ligaments which connect the different bones to each other, 
have a very strong resemblance to these tendinous parts, not 
only in their structure but in their qualities also. Many of them 
appear rather more firm in their texture and more vascular. 
Their vessels are also larger; their colour sometimes inclines to 
a dull white, and when examined chemically, they appear to 
differ, in some respects, from tendons. 

They agree, however, with the tendinous parts as to their in- 
sensibility in a sound state, and the extreme pain which occurs 
when they are inflamed. No nerves have been traced into their 
structure. 

Notwithstanding the ordinary insensibility of these parts, it 
was asserted by M. Bichat that several animals who seem to 
suffer no pain from cutting, puncturing, or corroding the liga- 
ments of their joints, appeared to be in great agony when these 
parts were violently stretched or twisted ; and he declared this 
to be the case when all the nerves which passed over the liga- 



FIBROUS TISSUE. 



211 



merits, and could have been affected by the process, were cut 
away. He explained by this the pain which sometimes occurs 
instantaneously in sprains, in the reduction of luxations, and in 
other analogous processes. 

The ultimate structure of these parts is, perhaps, not perfectly 
understood. 

An anatomist of the highest authority, Haller, appears to have 
considered them as formed of membrane, while a late writer, 
who has paid great attention to the subject, and is also, of high 
authority, M. Bichat, has satisfied himself that their structure is 
essentially fibrous. 

If a tendon, or portion of tendinous membrane, be spread out, 
or forcibly extended, in a direction which is transverse with re- 
spect to its fibres, it will seem to be converted into a fine mem- 
brane, and the fibres will disappear to the naked eye. The same 
circumstances will occur when a ligament is treated in a similar 
way; but much more force is required. 

Thus constructed, these parts are perfectly passive portions of 
the animal fabric, and have no more power of motion than the 
bones with which many of them are connected. 

But notwithstanding their ordinary insensibility, they often in- 
duce a general violent affection of the system when they are dis- 
eased. A high degree of fever, as well as severe pain, attends 
their acute inflammations; and hectical symptoms, in their great- 
est extent, are often induced by their suppurations. 

There is another circumstance in their history which is very 
difficult to reconcile with their ordinary insensibility. They are 
the most common seats of gouty painful affections. 

In these cases, pain does not seem to be the simple effect of 
inflammation : it often occurs as the first symptom of the disease; 
it frequently exists with great violence for a short time and goes 
off without inflammation, and it is frequently vicarious with af- 
fections of the most sensible and irritable parts. 

Parts of a tendinous and ligamentous structure do not appear 
retentive of life, but lose their animation very readily, in conse- 
quence of the inflammation and other circumstances which at- 
tend wounds. 



212 YELLOW ELASTIC LIGAMENTOUS TISSUE. 

When thus deprived of life, they retain their usual appearance 
and their texture a long time. The dead parts separate from 
the living in large portions, in a way which has a considerable 
analogy with the exfoliation of bones. 

The tendons and their expansions, and the various fasciae, 
have the same chemical composition. If boiled a long time, 
they dissolve completely, and form the substance called by chem- 
ists gelatine, or pure glue. 

The ligaments differ from them in some respects. When boiled 
they yield a portion of gelatine, and do not dissolve entirely ; but 
are said to retain their form and even their strength, after a very 
long boiling. The composition of the part so insoluble in water, 
has not yet been ascertained. 

Of the Yellow Elastic Ligamentous Tissue. 

— This is a modification of the common ligamentous tissue, 
which though not usually treated apart, differs from it in many 
essential particulars. It contains, according to the younger Gi- 
rard, some fibrine in its composition ; it is eminently elastic, and 
is placed to give resistance and support to parts, where in other 
animals, we meet with muscular fibres, for which it is in some 
sort a substitute. In some situations it is of a deep yellow co- 
lour, and rarely presents the silvery aspect of the common tissue. 
It forms the middle coat of the arteries, the ligaments between 
the bridges of the vertebras, the ligamentum nucha in quadru- 
peds with heavy pendant heads, the elastic involucrum of the 
corpus cavernosum and spongiosum penis in the male, of the 
clitoris in the female, and the elastic covering of the spleen; we 
might also add, the elastic membrane of the nose and ear, which 
are more allied to it, than to cartilage, though they are called 
membraniform cartilage. 

Of the Fibro- cartilaginous or Ligamento- cartilaginous Tissue. 

— There is another variety of the desmoid tissue, which holds a 
middle station between ligament and cartilage, partakes partly 
of the nature of both, and has been treated of by Bichat as a 
distinct tissue under this compound name. Vesalius and Mor- 



FIBRO-LIGAMENTOUS TISSUE. 910 

gagni, called them cartilaginous ligaments; Haase, mixed liga- 
ments. Like ligaments, they present a well marked fibrous ap- 
pearance, and are strong and resisting. Like cartilages, they are 
white, very dense and elastic. Beclard divides them into the 
temporary and permanent* 

— The temporary, are those which pass regularly and at deter- 
mined periods to the state of ossification, and are developed in 
the midst of the ligaments and tendons, as the patella and sesa- 
moid bones. 

— The permanent are of several kinds. 1. Those which are 
free at both these surfaces, and are lined by the synovial mem- 
brane. These constitute the interarticular or meniscous carti- 
lages, (menisci,) and are attached at their outer surface to the 
inner face of the capsular ligament. They are found in the knee, 
maxillary, clavicular, and lower ulnar articulations. 2. Those 
which are adherent by one of their surfaces ; these are found 
whenever the fibrous tissue is subjected to habitual friction by the 
tendons, as in the different grooves, through which they play, or 
upon the sides of the ligaments or cartilages, against which they 
rub; the periosteum, or whatever fibrous membrane it may be, 
first becomes thickened and then converted into a semicartilage. 
It also exists in the fibrous rings, placed at the margin of the 
glenoid and cotyloid cavities for the purpose of deepening their 
sockets. 3. Those adherent by both surfaces. These are found 
between the bodies of the vertebrae and the pubic bones. 
— The accidental production of this tissue is by no means un- 
common ; it is found occasionally in the cavities of fractures 
forming false joints, in the tubercular cavities of the lungs, in the 
uterus, ovaries, etc. 

* Bichat considered the elastic cartilaginous membranes of the nose, oar, and 
trachea, as belonging to this division of the tissues, but they certainly have a 
closer affinity to the yellow elastic fibrous tissue. — p. 



214 OF ARTICULATIONS 



CHAPTER IV. 

A GENERAL ACCOUNT OF ARTICULATIONS, AND OF BURSjE 
MUCOSAE. 

Of Articulations. 

Those surfaces of bones which form the movable articula- 
tions are covered with cartilaginous matter which has been al- 
ready described.* 

— In many of the immobile articulations, as the sacro-iliac 
symphysis for instance, a thin lamen of cartilaginous matter, with 
all the other appurtenances of joints, are likewise met with. The 
connexion between the articular cartilage and the bones is strong, 
but its nature is not well known. None of the vessels of the bone 
pass into the cartilage, but terminate in its immediate neighbour- 
hood. Gerdy (page 29) considers it a secretion from these ves- 
sels, and that its formation is like that of the cuticle, from the 
vessels of the skin. It presents the appearance of a couch of 
white wax spread over the end of the bones, though it is com- 
posed of vertical fibres like the frill of velvet, so crowded toge- 
ther as to leave no sensible interval between them, and presenting 
a free extremity to the cavity of the joint. The cartilages ter- 
minate insensibly at their circumference on the surface of the 
bone. On the heads of the bones they are thicker at the central 
part, than at their circumference; in the corresponding socket, 
the cartilaginous coating is thickest at the margin, and sometimes 
spreads out into a sort of cartilaginous rim. — 

They are retained in their relative situations by ligaments, 
such as have been lately mentioned, which are exterior to the 
cavities of the articulations, and placed in such situations that 
they permit the motions the joints are calculated to perform, 
while they keep the respective bones in their proper places. 

* See page 35. 



SYNOVIAL CAPSULES. 215 

Of the Synovial Capsules. 

— The synovial capsules are formed of an extremely thin 
transparent, double reflected tissue, the vessels of which circu- 
late in the healthy state only the serous portions of the blood, 
and which, though erected into a distinct tissue or system by Bi- 
chat, under the name of synovial, is now generally considered as 
forming only a part of the general serous tissue, which it closely 
resembles in structure, and with which it intimately sympathises 
in disease. They are of three kinds: 1st. Those which line the 
inner surface of the ligaments of the joints, and are reflected 
over the surfaces of the articular cartilages. These are called 
the articular synovial cartilages. 2d. Those which are placed be- 
tween the tendons of the muscles, and the bones and cartilages 
against which the tendons rub. These are called bursce mucosa. 
3d. Those which are placed between the skin and the bones, 
tendons, or other hard parts, over which it performs frequent and 
extensive movements. These are called the subcutaneous syno- 
vial capsules. — 

Of the Articular Synovial Capsules. 

They are invested in a particular manner by a thin delicate 
membrane, which in some joints, as those of the hip and shoul- 
der, seems to be the internal lamina of a stronger ligament 
called the capsular ; and, in other joints, the knee, for example, 
appears to be independent of any other structure. In each case, 
this synovial membrane, as it has lately been called, forms a 
complete sac or bag, which covers the articular surface of one 
bone, and is reflected from it to the corresponding surface of the 
other ; adhering firmly to each of the articulating surfaces, and 
extending loosely from the margin of one surface to that of the 
other. 

In the distribution it supplies the place of perichondrium to 
the cartilages, and of periosteum to those surfaces of bone with 
which it is connected. 

It seems greatly to resemble the membranes which line the 
abdomen and thorax, and invests the parts contained in these 
cavities ; and like them it may be termed a reflected membrane. 



216 BURS.E MUCOSAE. 

It is thin and very flexible, but dense and strong. 

It secretes, or effuses from its surface, a liquor, called synovia; 
which is particularly calculated to lubricate parts that move 
upon each other. 

The fluid is nearly transparent : it has the consistence of a 
thin syrup, and is very tenacious or ropy. It mixes with cold 
water, and, when heated, becomes milky, and deposits some 
pellicles without losing its viscidity. It appears to be composed 
of eighty parts in one hundred of water; above eleven parts of 
fibrous matter; and between four and five parts of albumen. It 
also contains a small portion of soda, of muriate of soda, and of 
phosphate of lime. 

There are in many of the joints masses of fat which appear 
to project into the cavity, but a> - . exterior to the synovial mem- 
brane, and covered by it; as the viscera in the abdomen are 
covered by the peritoneum. 

They are generally situated so as to be pressed gently, but not 
bruised, by the motions of the bones. 

In some joints, they appear like portions of the common adi- 
pose membrane ; in others, they appear more vascular, and have 
a number of blood-vessels spread upon them. Small processes 
often project from their side-like fringe. 

These masses have been considered as synovial glands; but 
they do not appear like glands; and it is probable that the syno- 
via is secreted by the whole internal surface of the membrane.* 

The synovial membrane, like the other parts of joints, is in- 
sensible in a sound state, but extremely painful when inflamed. 
The synovia, which is secreted, during the inflammation of this 
membrane, has a purulent appearance. 

Of Burses Mucosa. 

There are certain membranous cavities called bursas mucosas, 
which are found between tendons and bones, near the joints, 

* Clopton Havers, ignorant that the synovia was derived by a sort of perspira- 
tion from the inner surface of this membrane, supposed it to be secreted by these 
masses of adipose matter, which are still known, in perpetuation of his mistake, as 
Havers' glands. — p. 



BURSiE MUCOSAE. 217 

and in other places also, which have so strong a resemblance to 
the synovial membrane, and are so intimately connected with 
some of the articulations, that they ought now to be mentioned. 

They are formed of a thin dense membrane, and are attached 
to the surrounding parts by cellular substance; they contain a 
fluid like the synovia; and sometimes there are masses of fat, 
which, although exterior to them, appear to project into their 
cavities. 

There is, commonly, a thin cartilage, or tough membrane, 
beween them and the bone on which they are placed. 

They often communicate with the cavities of joints, without 
inducing any change in the state of the part. 

As they are always situated between parts that move upon 
each other, there is the greatest reason to believe that they are 
intended to lessen friction.* 

These bursas mucosas are very numerous, as will appear from 
a subsequent account of them. 

Several of them are very interesting on account of their con- 
nexion with very important joints. 

— These bursas form synovial sheaths to the tendons, where 
they run through grooves in the bones, or under their vaginal 
ligaments, or where they glide over each other, as in the palms 
of the hands and the soles of the feet : but they are especially 
met with, wherever a tendon changes its direction, and converts 
a bone, a cartilage, or ligament into a pulley; of which instances 
will be detailed hereafter. When a bursas, or tendinous sheath, 
invests a tendon about to subdivide, as the flexor tendons of the 
fingers at the wrist, the sheath also subdivides so as to send a 
process along each parting tendon; a knowledge of which fact 
is of importance to the surgeon, as this membrane when injured, 
is much disposed to continuous inflammation. 
— The number of these bursas vary in different individuals. 
Ollivier reckons them at one hundred pairs. 

* For farther information respecting 1 this subject, as well as joints in general, 
the reader is referred to a Description of the Bursas Mucosae of the Human Body, 
by Alexander Monro ; to whom the world is so much indebted for the elucidation 
of many important points in anatomy and physiology. 
VOL. I. 19 



218 SUBCUTANEOUS SYNOVIAL CAPSULES. 

Subcutaneous Synovial Capsules. 

— These have been long observed about the wrist, ankle and 
knee, where they sometimes attain the size of walnuts, and are 
known to surgeons under the names of ganglions and hygroma. 
They were studied and described for the first time, however, by 
Beclard. They exist wherever the skin is strongly and fre- 
quently moved over a resisting part: as between the skin and the 
patella; between the olecranon and skin; over the trochanter ; 
acromion; thyroid cartilage; at the metacarpal and metatarsal 
articulations, &c. &c. They are developed accidentally in dif- 
ferent parts, when from any cause, as in curvature of the spine, 
the friction of the tendons is increased. When inflated, the ca- 
vities appear oblong and cellulated, contain some synovial fluid, 
and look like dilated cells of the cellular tissue, of which they 
are in all probability formed; many of them, however, are visible 
in the foetus during the latter period of utero-gestation. — 



PARTICULAR ARTICULATIONS. 219 



CHAPTER V. 

OF PARTICULAR ARTICULATIONS. 
The connexion of the Head with the Vertebrce. 

The condyles of the occipital bone, and the corresponding 
cavities of the atlas, are covered with cartilage. The condyle 
and cavity on each side are invested with a synovial ligament, 
as described in the general account of articulations. 

An anterior ligament, (ligamentum occipito-atloidal anterior,) 
descends from the front part of the great occipital foramen, and 
is inserted into all the front part of the atlas, between its articu- 
lating processes. That portion of this ligament which is in the 
middle, and inserted into the tubercle of the atlas, appears 
stronger, and is distinct from the rest of it. 

A posterior ligament, (ligamentum occipito-atloidal posterior,) 
passes from the posterior margin of the occipital foramen to the 
upper edge of the posterior arch of the atlas. 

From each side of the upper end of the tooth-like process of 
the vertebra dentata, a ligament (oblique, or moderator,) passes 
upwards and outwards, to be inserted into the internal side of 
the basis of each condyle of the occipital bone. There is a small 
lio-ament, called the middle straight ligament (ligamentum me- 
dium rectum,) which passes from the tip of the dentated process, 
to be inserted on the inner face of the occipital foramen between 
the insertion of the moderator ligaments. 

From the anterior margin of the great occipital foramen, a 
ligament passes down on the inside of the vertebral cavity, over 
the tooth-like process, which is inserted in the body of the verte- 
bra dentata, and the ligaments connected with it. This liga- 
ment is composed of a number of fibrous bands called by Cal- 
dani, lacerti liga)nentosi. 



220 ARTICULATIONS OF THE VERTEBRA. 

There is also a ligament which runs across from one side of 
the atlas to the other, to confine the tooth-like process in its an- 
terior cavity, (transverse ligament, ligamentum transversale at- 
lantis.) This ligament adheres above to the occipital bone, and 
below to the body of the vertebra dentata. The anterior sur- 
face of the tooth-like process plays on the anterior arch of the 
atlas ; the posterior surface plays on this ligament. A synovial 
capsule is placed on each surface of the tooth-like process. 

The articulating surfaces of the oblique process of the atlas 
and vertebra dentata on each side, are invested by a synovial 
membrane. There are, also, additional ligaments placed before 
and behind these processes, that have an effect on their motions. 

The uses of these different ligaments are very obvious when they are dis- 
sected. The transverse ligament of the atlas, with the synovial mem- 
branes, form an articulation for the tooth-like process, which is of a pecu- 
liar kind. The ligaments that pass from this process, to the bones of the 
condyles of the occipital bone, must have an effect in restraining the rota- 
tion of the head and atlas on this process, and therefore have been called 
moderator ligaments. 

The Articulations of the Vertebrce with each other. 

To acquire a perfect idea of the construction of the Spine it is necessary to 
examine at least two preparations of it : in one of which the bodies of the 
vertebrae should be sawed off from the processes, so that the spinal canal 
may be laid open. 

The bodies of all the vertebrae, except the atlas, are connected 
to each other by the intervertebral fibro-cartilaginous matter de- 
scribed in page 121, which unites them very firmly, at the same 
time that it allows of some motion, in consequence of its elasti- 
city and compressibility. This connexion is strengthened by 
two ligaments, which extend the whole length of the spine, from 
the second cervical vertebra to the sacrum. 

The first of these, denominated the anterior vertebral ligament, 
covers a considerable part of the anterior surface of the bodies 
of the vertebras; it is thickest in the middle, and varies in its 
breadth in different parts of the vertebral column ; it adheres 
very firmly to the intervertebral substance, and not so firmly to 



ARTICULATIONS OF THE VERTEBRAE. 



221 



the bodies of the vertebrae. It has the shining silver-like appear- 
ance of tendon, and seems to consist entirely of longitudinal 
fibres. There are many fibres which appear to be connected 
with it, that do not extend the whole length of the spine. 

On the posterior surface of the bodies of the vertebras, in the 
cavity which contains the spinal marrow, is the posterior or in- 
ternal vertebral ligament, which, like the anterior, extends from 
the upper part of the spine to the sacrum. 

In its progress downwards it is broader where it is in contact 
with the intervertebral matter, and narrower about the middle 
of each of the bodies of the vertebras. It appears to consist of 
longitudinal tendinous fibres, which are similar to those of the 
anterior ligament. The fibres of which these ligaments are 
composed, are more closely connected by origin and insertion 
with the intervertebral matter, than with the bodies of the ver- 
tebras. Some of the fibres are inserted into the next vertebrae 
or intervertebral substance below their place of origin, others 
into the second or third, and some into the fourth or fifth. 

The oblique processes of the vertebrae are covered with car- 
tilage, and are invested with a synovial membrane, like the other 
movable articulations. In the neck and back these membranes 
are thin and delicate; but in the loins they are blended with liga- 
mentous fibres which give them additional strength. 

Some of the most curious and interesting ligaments of the 
spine, or indeed of the body, are those which are attached to the 
bony plates or arches that extend from the oblique to the spi- 
nous processes of each vertebrae. These plates form a great 
portion of the posterior part of the vertebral canal and the va- 
cant spaces between them are filled up by these ligaments, which 
extend from the plates of each upper vertebra to those of the 
next vertebra below. 

They are situated between the spinal process and the oblique 
processes on each side. 

They are, therefore, two distinct ligaments between the two 
vertebrae, one on each side of the spinal process ; and as they 
extend only from the plates or arches of one vertebras to those 
of the other, they must necessarily be very short. They are 

19* 



222 ARTICULATIONS OF THE VERTEBRAE. 

much more conspicuous on the internal surface of the vertebral 
cavity than they are externally. They are thick and substantial, 
and very elastic; their colour resembles that of a yellowish 
adeps ; and from that circumstance they are called by some 
anatomists the yellow ligaments. They complete the cavity for 
the spinal marrow. There are twenty-three pairs in all. 

As the plates or arches to which they are conaected must re- 
cede from each other, when the spine is bent forwards, it seems 
that they should be elastic. 

There are also ligaments between the spinous processes, 
which extend from the under surface of" one spinous process to the 
upper surface of the spinous process below it. These are com- 
posed of tendinous shining fibres, and are sufficiently loose to 
permit the anterior flexure of the vertebral column. From their 
situation they are denominated interspinal ligaments. 

There is also a thin and narrow ligamentous band, which ex- 
tends from the spinous process of the seventh cervical vertebra 
to the spinous processes of the os sacrum, and adheres to the ends 
of the intermediate spinous processes. It is exterior to the ten- 
dinous origins of the trapezii and latissimi dorisi muscles. The 
upper portion is slightly connected to the trapezius, the lower 
part adheres more firmly to the latissimus dorsi. 

The ligamentum nucha;, ligament of Diemerbrceck, as it has 
been denominated, is a narrow but firm strip, which extends 
from the spinous process of the last cervical vertebra, to the oc- 
cipital bone, at or near its protuberance. That portion of the 
trapezius muscle which is between the occipital bone and the 
seventh cervical vertebra, originates from it, or is intimately 
connected with it ; and a portion of the splenius muscle is also 
connected with it. 

From the internal surface of this ligament, a thin tendinous 
membrane arises, whose fibres run obliquely upwards and for- 
wards, and are inserted into the spinous processes of each of the 
cervical vertebrae above the seventh, and also into the atlas and 
the os occipitis. Attached to the ligamentum nucha? and to the 
spine, this membrane seems like a partition between the muscles 
which lie on each side of the back of the neck. 



ARTICULATION OF THE LOWER JAW. 223 

After inspecting the different ligaments of the spine, it will be obvious that 
the yellow ligaments are among the most important of them ; in conse- 
quence of their position, their strength, and their elasticity. 

Articulation of the Lower Jaw, ( Temporo-maxillary.) 

The glenoid cavity of the temporal bone with the tubercle be- 
fore it, and the condyle of the lower jaw, are covered with car- 
tilages. A cartilage is placed between them called interarticu- 
lar, which being flexible, is accommodated to the convexity of 
the condyle and hollowness of the glenoid cavity, and also to 
the figure of the aforesaid tubercle to which it is extended- A 
synovial capsule, or bag, invests the glenoid cavity and the tu- 
bercle, and covers the upper surface of the cartilage. A second 
capsule of the same kind is attached to the condyle of the lower 
jaw, and the lower surface of the cartilage. A few ligamentous 
fibres extend from the circumference of the cavity and tubercle 
of the temporal bone, over both synovial capsules and the carti- 
lage between them, to the lower jaw below the condyle, and ap- 
pear to be attached to the cartilage. 

These fibres are collected in such numbers, on the external 
and internal sides of the articulation, that they have been called 
the external and internal lateral ligaments. 

Another ligament called stylo-maxillary, is mentioned which 
arises from the styloid process of the temporal bone, and is in- 
serted into the lower jaw near its angle ; but this seems rather 
appropriated to the stylo-glossus muscle than to this articula- 
tion. 

In consequence of this structure, the condyle of the lower 
jaw moves out of the glenoid cavity upon the tubercle, when the 
mouth is opened widely. 

Articulation of the Clavicle and Sternum, called Sterno-cla- 

vicular. 

The connexion of the clavicle and sternum resembles strongly 
that of the lower jaw and temporal bone. A movable carti- 
lage is placed between the articulating surfaces, with a distinct 
synovial capsule on each side of it, applied in the usual manner 



224 ARTICULATIONS OF THE SHOULDER. 

to the corresponding surface of the clavicle and of the sternum. 
Exterior to these capsules and the intervening cartilage, are 
many ligamentous fibres, which are most numerous on the ante- 
rior and posterior surfaces, but diverge from each other as they 
proceed from the clavicle to the sternum, and are, therefore, 
called Radiated Ligaments. 

There is a strong ligament called the Interclavicular, which 
passes across the sternum internally, from one clavicle to the 
other. 

And another ligament, which arises from the inferior rough 
surface of the clavicle, near the sternum, which is inserted into 
the cartilage of the first rib. 

This is called the Rhomboid, or Costo-clavicular ligament. 

Articulations of the Clavicle and Scapula, (Scapulo-clavicular.) 

These are two in number ; one which connects the acromion 
and external end of the clavicle called acromio- clavicular, and 
one which connects the lower surface of the outer part of the 
clavicle with the coracoid process of the scapula, called coraco- 
clavicular. 

Acromio- clavicular. The small surfaces of the clavicle and 
scapula, which are in contact with each other, are furnished 
with the apparatus of a movable articulation. They are co- 
vered with cartilage, and are invested with a small synovial 
capsule. The upper and lower surfaces of the extremities of the 
clavicle and acromion are covered by a ligamentous membrane, 
which is called, from its situation, the superior and inferior liga- 
ment of this articulation. 

Coraco-clavicular, consisting of two portions, conoid and trape- 
zoid. But these bones are more firmly connected by the liga- 
ment which passes to the coracoid process of the scapula from 
the under side of the clavicle, and is very strong. Some of the 
fibres which compose this ligament are so arranged that they 
have the appearance of an inverted cone : the remaining fibres 
appear like another ligament, and therefore they have been 
called the trapezoid and conoid ligaments. 

— The base of the conoid ligament is upwards, and its apex 



ARTICULATIONS OF THE SHOULDER. 



225 



or origin is at the root of the coracoid process. It is the stronger 
of the two. The trapezoid is at the outer side of the conoid. 
It is broad and thin, with its fibres separated by interstices. It 
rises from the root of the coracoid process, and is inserted on 
an oblique ridge, leading from the tubercle of the clavicle to its 
acromial end. — 

By their situation and strength they are enabled to retain the 
bones in their proper relative positions, at the same time that 
they permit a peculiar rotary motion. 

— There is a bifid ligament called ligamenium bicorne, arising 
from the root of the coracoid process, at the inner side of the 
conoid, which runs inwards in front of the subclavius muscle, 
to which it serves as a fascia, and bifurcates ; one horn is at- 
tached to the under surface of the clavicle near the rhomboid 
ligament, and the other to the end of the first rib, under the ten- 
don of the subclavius muscle. — 

Articulation of the Os Humeri and Scapula, (Scapulo- humeral.) 

The spherical portion of the upper extremity of the os humeri 
is the part of that bone which is principally concerned in the 
articulation, and is covered with cartilage; as is also the gle- 
noid cavity of the scapula. 

The glenoid cavity of the scapula, which is so small in the 
dried bone when compared with the head of the os humeri, is 
enlarged by the long tendon of the biceps muscle, which is at- 
tached to the upper edge of its margin, and then divides and 
passes down on each side of the cavity, increasing the breadth 
of it considerably, thus forming what is called the glenoid liga- 
ment, deepening the socket, and giving greater latitude of motion 
to the arm, from its elasticity, than if the socket had all been 
formed of bone. It appears to be blended with the cartilage 
that lines the cavity, and also with the capsular ligament which 
is exterior to it. 

The articulating surface, thus composed, is perfectly regular 
and uniform. 

The synovial ligament, in this articulation, is so blended with 
an externa! stronger ligament, that it cannot be separated in the 



226 ARTICULATIONS OF THE SHOULDER. 

recent subject ; but, notwithstanding, it is applied to the articu- 
lating surfaces in the same way that it is applied to the other 
joints forming a capsule. The stronger exterior lamina is, of 
course, only applied to that part of the synovial capsule which 
proceeds from the margin of one cartilaginous articulating sur- 
face to the other : it appears to be most intimately connected 
with the periosteum, and is rendered more firm and thick in par- 
ticular parts, by the addition of fibres from the tendons of the 
supra and infra-spinatus, and subscapularis muscles with which 
it is blended. 

It arises from the scapula at a small distance from the margin 
or edge of the glenoid cavity, as formed by the tendon of the 
biceps, and is inserted into the os humeri at a small distance 
from the edge of the cartilaginous articulating surface; and, if 
dissected away from the bones, would appear like a cylindrical 
bag with both extremities open. — The capsular ligament is thick- 
ened in front by a band of fibres, arising from the outer part of 
the back surface of the coracoid process, which proceeds beneath 
the triangular ligament to the upper part of the os humeri ; it is 
closely blended with, and forms a part of the capsular ligament, 
and is denominated the coraco-humeral ligament, or ligamentum 
adscititium. — 

The long tendon of the biceps muscle, in the groove at the 
head of the os humeri, appears to penetrate this ligament; but 
it is not within the cavity of the synovial membrane ; for this 
membrane sends down a process like the finger of a glove, which 
lines the groove, and is reflected from its surface upon the sur- 
face of the tendon, and covers it during its whole extent, being 
reflected from the tendon, at its upper termination, to the adjoin- 
ing surface; so that the tendon is in fact outside of the synovial 
capsule, which, therefore, confines the synovia completely. 

This capsular ligament, which is one of the strongest, would 
not avail much in keeping the bones in their proper situations, if 
the muscles and their tendons were not disposed in such a man- 
ner, that when the muscles act, their power is excited to the same 
effect. In some cases of paralytic affection, where the muscles 
exert no influence, the weight of the arm, when it is allowed to 



ARTICULATION OF THE ELBOW. 

227 
hang without support, draws the head of the os humeri, below 
the glenoid cavity, notwithstanding the capsular ligament. At 
the same time it ought to be observed, that this ligament must be 
lacerated in every case of complete luxation of the os humeri ; 
as it cannot possibly distend sufficiently to permit the separation 
of the bones to the extent which then takes place. 

The Articulation of the Elbow. 

Those surfaces of the os humeri, ulna, and radius, which 
move upon each other, are covered with cartilage. 

The motion of the ulna and radius on the os humeri is that 
of the simple flexion and extension. The cylindrical head of 
the radius performs a part of a revolution, nearly on its own 
axis, without moving from the depression in the side of the ulna, 
with which it is in contact. 

The synovial membrane adheres very firmly to the surface 
covered with cartilage on each of the bones, and is reflected 
from the margin of this surface, on one bone, to that of the 
others. As the principal motion performed is hinge-like, the 
principal ligaments are on the sides. There is also a circular 
ligament, which arises from the ulna and invests the narrow part 
of the radius immediately below its cylindrical head like a loop, 
to confine the radius in contact with the ulna, and at the same 
time permit its motion. 

This ligament is so blended with the synovial membrane, that 
it sometimes cannot be separated from it. 

The lateral ligaments are denominated from their origin and 
insertion, Brachio-radial, and Br achio- cubital, or Internal and 
External. The ligament which invests the neck of the radius is 
called Coronary or Orbicular. 

There are also some ligamentous bands, which run upon the 
front and back parts of the joint to strengthen it, which are called 
Anterior and Posterior accessory ligaments. Within the syno- 
vial membrane, in the upper margins of the depressions for the 
olecranon and coronoid processes of the ulna, are the adipose 
substances usually found in joints. 



g28 ARTICULATION OF THE WRIST. 

Articulation of the Wrist. 

The structure of the wrist is particularly complex, because it consists of 
three articulations, which are contiguous to each other, viz. That of the 
ulna and radius; of the radius and first row of carpal bones; and of the 
first and second row of carpal bones with each other. 

An oblong convex head is formed by the upper surfaces of 
the scaphoides and lunare, and a portion of the upper surface 
of the cuneiforme bone. This head is covered by one cartilage, 
which is so uniform that the different bones cannot be distin- 
guished from each other. The lower end of the radius is arti- 
culated with this head, but does not cover the whole of it ; a 
portion of this head, therefore, is under the ulna, but not in con- 
tact with that bone : for the cartilage which lines the concavity 
of the radius, is continued beyond the radius, so as to cover the 
remainder of the head, formed by the carpal bones. The lower 
end of the ulna is in contact with the upper surface of this car- 
tilage, and is articulated laterally with the semilunar cavity of 
the radius. This semilunar cavity is lined by a cartilaginous 
process, continued from the upper surface of the aforesaid car- 
tilage ; so that the extremity and the side of the ulna play upon 
the cartilage continued from the radius. This articulation of the 
ulna and radius is distinct from that of the radius and carpus. 

A synovial membrane covers the articulating head formed by 
the three bones of the carpus, and is reflected from the margin 
of their cartilaginous surface, to the cartilage at the end of the 
radius. A plait or fold of this membrane passes from the head 
of the carpus, at the junction of the scaphoides and lunare, to 
the opposite part of the cartilage of the radius, and has been 
called the Mucous Ligament, (ligamentum mucosum.) 

A strong ligament (internal lateral) is placed on the internal 
side of this articulation, which arises from the styloid process of 
the ulna, and is inserted into the anterior transverse ligament 
which confines the flexor tendons, and into the ligament of the 
os pisiforme. 

Another ligament, (external lateral,) on the external side, arises 
from the styloid process of the radius, and is inserted into the 



ARTICULATION OF THE WRIST. 229 

scaphoides, some of its fibres being continued into the aforesaid 
transverse ligament, and the trapezium. 

There are two broad irregular ligamentous membranes: one 
of which arises from the anterior margin of the articulating sur- 
face of the radius ; and the other from the posterior margin. 
One of them is inserted anteriorly, and the other posteriorly, into 
the margin of the corresponding surface of the scaphoides, 
lunare and cuneiforme. They adhere to the synovial membrane ; 
but in some places this membrane appears through apertures 
which are in them. 

The surfaces, by which the first and second rows of carpal 
bones are articulated with each other, are very irregular. The 
magnum and part of the unciforme form a prominent oblong 
head ; on each side of which is a much lower surface, formed 
by the trapezium and trapezoides externally, and the remaining 
portion of the unciforme internally.* 

The scaphoides, lunare, and cuneiforme, form a cavity which 
corresponds with this head, and also with the lower surface 
formed by the unciforme; while another surface of the sca- 
phoides is articulated with the trapezium and trapezoides. These 
corresponding surfaces, formed by the two rows of carpal bones, 
irregular as they are, compose but one articulation, which is ca- 
pable of a limited flexion and extension. It has a synovial mem- 
brane, with two lateral ligaments, and an anterior and posterior 
ligament ; these last, however, are short, and can be best exa- 
mined from within, by cutting open the articulation. 

The bones of each row move laterally upon each other. Their 
lateral surfaces, which are in contact, are covered with carti- 
lage; and the synovial sac which exists between the first and 
second row of bones, sends off" processes between these surfaces, 
which are disposed like the ordinary synovial membranes in 
other articulations ; adhering to each of the cartilaginous sur- 
faces, while they communicate with the larger cavity between 
the two rows. 

* The palm of the hand is supposed to present forward. 
vol. i. 20 



230 ARTICULATION OF THE CARPAL BONES, &c. 

Articulation of the Carpal and Metacarpal Bones. 

The metacarpal bones are connected to the last row of the 
carpus by surfaces which are covered with cartilages, and sup- 
plied with synovial membranes, as the most movable articula- 
tions are ; but the ligaments which connect these bones do not 
permit much motion between them. The ligaments are all dor- 
sal and palmar. The irregularity of the articulating surfaces of 
the metacarpal bones of the index and middle finger also con- 
tribute to restrain their motion ; and these bones accordingly 
move less than the other two metacarpal bones, whose surfaces 
are better adapted for motion. 

Articulation of the Fingers. 

The first joint of the fingers has a large synovial membrane, 
which invests the head of the metacarpal bone and the corre- 
sponding cavities of the bones of the first phalanx. On each 
side is a strong lateral ligament, which arises from the side of 
the head of the metacarpal bone, and is inserted into the side of 
the base of the first phalanx. 

Anteriorly there is also a ligament, which, although thick and 
strong, is very flexible. It is thickened by cartilaginous nv.tter 
on its palmar face, which serves as a sort of pully to the ten- 
dons, and increases their power by removing them from their line 
of action. Posteriorly the expansion of the tendons of the ex- 
tensor muscle, and the tendons of the interossei, have the effect 
of a ligament. 

The different phalanges are articulated with each other in a 
similar manner. The lateral ligaments are very strong : the 
tendon of the extensor covers the articulation posteriorly ; and 
anteriorly, under the flexor tendons, there is a soft, but thick 
ligamentous substance. The metacarpal bone of the thumb dif- 
fers greatly from the other metacarpal bones in its articulation 
with the wrist, as respects its motions. The articulating sur- 
faces are calculated for lateral motion as well as flexion and ex- 
tension ; and there are no ligaments which prevent it. Its cap- 
sular ligament forms a complete sac. The first joint of the 



ARTICULATION OF THE RIBS. 



231 



thumb resembles considerably that of the fingers ; and the se- 
cond joint resembles the last of the phalanges. 

Articulation of the Ribs. 

The ribs are connected to the bodies of the vertebrae and the 
intervertebral cartilages, by one articulation, and to the trans- 
verse processes of the vertebrae by another: these articulations 
have the ordinary apparatus for motion, with capsular ligaments, 
which in one case pass from the heads of the ribs to the bodies 
of the vertebrae, and in the other from the tubercles to the trans- 
verse processes. These form what are called the costo-vertebral , 
and costo-transverse articulations. 

— The capsular ligament of the costo-vertebral articulation, is 
not complete. It is much thickest in front and upon the sides, 
and radiates from its origin on the head of the ribs, whence it is 
usually called the anterior or radiating ligament. 
— There is also a small inter-articulating ligament, in this articu- 
lation, which passes from a ridge on the head of the rib to a cor- 
responding line on the intervertebral substance. It thus divides 
the joint into two halves, each of which has a separate synovial 
membrane. This ligament does not exist where the ribs are at- 
tached to a single vertebrae, as the first, eleventh and twelfth. 
— The costo-transverse articulation, besides its feeble capsular 
ligament and synovial membrane connecting the tubercle of the 
rib with the facet of the transverse process, includes three other 
ligaments, the internal transverse, the external transverse, and the 
middle costo-transverse. 

— The internal transverse, arises from the inferior margin of the 
transverse process, and is inserted into the upper margin of the 
neck of the rib below. 

— The external transverse, arises from the extremity of the 
transverse process and is inserted into the corresponding rib, just 
beyond the tubercle. 

— The middle costo-transverse ligament is extended between the 
neck of the rib and the contiguous transverse process. To be 
well seen it is necessary to saw longitudinally through the neck 
of the rib and its transverse process. — 



232 HIP Joint. 

These ligaments permit the motions necessary for respiration, 
and restrain all others. 

The connexion of the ribs anteriorly with their cartilages, is 
such as admits of no motion whatever between them ; but the 
extremities of the cartilages are articulated with the sternum, 
at the pits on the edges of that bone. In many instances there 
is no appearance of synovia between the ends of the cartilages 
and the sternum ; but this fluid is mostly to be found in the pits, 
on the lower extremity of the sternum. 

— In the articulations between the cartilages of the ribs and 
the sternum, there is a synovial membrane, and two ligaments, 
anterior and -posterior. These radiate from the sternal end of 
the cartilage, one over the anterior, the other over the posterior 
face of the sternum, and are blended with its periosteum. — 

The Hip Joint. 

The acetabulum is lined with cartilage ; and the brim or mar- 
gin of it is much enlarged, and the cavity deepened, by the 
addition of fibro-cartilaginous matter, which forms a regular 
smooth edge. This cartilaginous ring is continued across the 
upper part of the notch in the acetabulum ; so that it completes 
the circular margin of the cavity, but leaves the under part of 
the notch open. This forms what is called the cotyloid liga- 
ment. The head of the os femoris is covered with cartilage, but 
the depression in it is still visible. From this depression a strong 
round ligament (ligamentum teres or rotundum) arises, which 
appears to pass into the depression, near the centre of the ace- 
tabulum ; but actually terminates in the lower edge of the car- 
tilaginous ring or margin, where it crosses over the notch, and 
not in the bone. This ligament is in fact divided into two parts 
at its insertion ; one passes out at the inferior part of the coty- 
loid notch and is inserted on the margin of the ischium ; the 
other runs to the superior end of the notch, and besides being 
blended with the cotyloid ligament, is attached to the margin of 
the acetabulum. The thin {synovial) membrane with which this 
ligament is invested extends to the centre of the acetabulum, and 



KNEE JOINT. 233 

has given rise to the opinion that the ligament was inserted in 
the bottom of the acetabulum.* 

This ligament allows the head of the os femoris to rise out of 
the acetabulum, but it is probably torn in every luxation of the os 
femoris. 

The capsular ligament, which contains these articulating parts, 
is the strongest in the body. It arises around the acetabulum, 
near the basis of the cartilaginous brim, but it does not ad- 
here to the cartilaginous edge ; and it is inserted into the os 
femoris, near the roots of the trochanters, so that it includes 
a large portion of the neck of the bone. It is not every where 
of the same thickness and strength ; for, in various places, there 
are additional ligamentous fibres. The largest portion of these 
additional fibres appears to arise from the inferior anterior 
spinous process of the ilium. It is thinnest at its internal and 
posterior part. 

The synovial membrane forms the internal lamina of this liga- 
ment : it invests the articulating surfaces in the usual manner, 
and being reflected from the internal surface of the capsular 
ligament to the neck of the os femoris, it is in the place of peri- 
osteum to that part of the bone. 

It seems probable that this membrane is so reflected and ar- 
ranged, that the internal ligament is covered by it also, and, of 
course, that this ligament is exterior to the synovial membrane. 

There is a considerable quantity of adipose matter near the ter- 
mination of the aforesaid internal ligament, which is also exterior 
to the synovial membrane : some of this can be pressed out of 
the acetabulum, at the vacuity in the notch under the cartilagi- 
nous margin. 

Articulation of the Knee. 

The synovial membrane of the knee joint is, in some places, 
without the support of a proper capsular ligament, or external 
lamen, so that it is easier distinguished in this articulation than 
in many others. 

It adheres firmly to the cartilaginous surfaces of the os femo- 

* See motions of skeleton. 
20 * 



234 KNEE JOINT. 

ris, tibia, and patella, and is reflected in the usual manner from 
one to the other of these surfaces. It arises closely from the 
edge of the cartilaginous surface at the top of the tibia ; but on 
the anterior part of the os femoris, it is continued to some dis- 
tance from the margin of the pulley-like surface, and the edges 
of the condyles. On each of the portions of the cartilaginous 
surfaces of the tibia is a cartilage of a semilunar form, so placed, 
that its convex edge rests on the margin of the cartilaginous 
surface, and its concave edge is internal. These cartilages are 
thick at their external, and very thin at their interna] edges ; so 
that they form two superficial concavities on the top of the tibia. 

Their extremities are attached by ligaments to the central 
protuberance of the tibia, and their anterior extremities are also 
connected by a ligament to each other. 

The synovial membrane is so reflected as to cover the whole 
surface of these cartilages, except the exterior edge, which is 
connected with the external ligaments of the articulation. 

The use of these cartilages, is evidently to form concavities 
on the top of the tibia, for accommodating the condyles of the 
os femoris; and upon examination, they will not appear so ano- 
malous as they are at first view, for there is a considerable ana- 
logy between them and the cartilaginous edges of the glenoid 
cavity and of the acetabulum. These are called the semi-lunar 
cartilages. The internal is but little more than a semicircle; 
the external is nearly circular in its shape. 

The patella appears to project into the cavity of the joint, and 
its internal surface is very prominent ; around the margin of this 
surface, and especially at the under part of it, the adipose sub- 
stance found in joints is very abundant. On each side of the adi- 
pose mass, under the patella, is a plait of the synovial membrane, 
called ligamentum alare minus, and majus; and a process of the 
membrane, called ligamentum mucosum, passes from the neigh- 
bourhood of the adipose mass to the os femoris between the 
condyles. 

These processes retain the adipose substance in its proper 
place, during the motions of the joint. 

There are two very strong ligaments, called the anterior and 



KNEE JOINT 235 

posterior crucial, which arise from the middle protuberance of 
the tibia, one of which is inserted posteriorly into the corner face 
of the external condyle of the os femoris, and the other, into the 
outer face of the internal. These ligaments decussate each 
other partially, on which account the name crucial is applied to 
them. They are in a state of tension when the leg is extended, 
and prevent it from moving farther forward : when it is bended 
they are relaxed. They add greatly to the strength of the con- 
nexion between the os femoris and tibia. 

These ligaments are generally supposed to be in the cavity of 
the joint; but the synovial membrane is reflected round them in 
such a manner that they are exterior to it. 

In addition to the crucial ligaments, this articulation has the 
following external supports. 

When the leg is extended, these ligaments are tense, they 
therefore prevent rotation in the extended state : when the leg is 
bent, they are relaxed, and, therefore, admit of that motion. 

1. Tivo strong lateral ligaments, one on each side of the knee; 
the external of which arises from the tubercle above the exter- 
nal condyle of the os femoris, and is attached to the fibula a lit- 
tle below its head; and the internal, from the upper part and tu- 
bercle of the internal condyle, and is inserted into the upper and 
inner part of the tibia. 

2. The posterior ligament, or ligament of Winslow, whose 
fibres run obliquely from the external condyle, to the back part 
of the internal side of the head of the tibia. This ligament also 
prevents the leg from being drawn too far forwards. 

3. The connexion of the tendons of the extensor muscles of 
the leg, with this articulation, has a great effect upon it. Their 
insertion into the patella places them in the situation of the up- 
per part of the anterior ligament, of which the very strong liga- 
ment, that passes from the lower margin of the patella to the 
tubercle of the tibia, is only the lower portion; while the patella 
may be considered as an inducted part of the ligament. The 
tendons of the ham-string muscles, also, serve to strengthen the 
articulation on the back and sides. 

— The fascia lata of the thigh as it passes down upon the leg, 



236 ARTICULATION OF THE TIBIA AND FIBULA. 

is thickened by a process of the extensor tendons, and forms a 
strong external investment or involucrum to the knee joint. It 
constitutes in fact a sort of capsular ligament to the joint ; it 
closely embraces the patella and its ligaments, covers in and is 
partly blended with the lateral ligaments, and is firmly attached 
to the condyles. At the posterior part of the joint, it forms a 
thin membrane, and can scarcely be traced. Its place is there 
supplied by the posterior ligament. On either side of the liga- 
ment of the patella its inner face is in contact with the synovial 
membrane of the joint. — 

Articulation of the Tibia and Fibula. 

The surfaces of the upper extremities of the tibia and fibula, 
which are articulated with each other, are very small. When 
the bones are in their natural position, these surfaces are nearly 
horizontal, that of the tibia looking down, and that of the fibula 
looking up : they are covered with cartilages, and have a syno- 
vial membrane. This articulation is supported by some liga- 
mentous fibres, which have been called anterior and posterior liga- 
ments ; but it is strengthened by the external lateral ligament 
of the knee, and by the tendon of the biceps muscle which is 
inserted into the upper end of the fibula. 

At their lower extremities, the cartilaginous crust, which, on 
each of them, forms part of the articulating surface with the as- 
tragalus, is turned up on their lateral surfaces, which are in con- 
tact with each other ; so that a small portion (equal in breadth 
only to one-sixth of an inch) of the contiguous surfaces, is co- 
vered with cartilage ; the other parts of these surfaces which 
are very considerable, are attached to each other by the inter- 
vention of fibrous or membranous matter, and there is very little 
motion of the bones on each other. 

There are very strong external ligaments, anteriorly and pos- 
teriorly, which connect the fibula to the tibia ; and from the pos- 
terior end of the fibula a small short ligament passes to the near- 
est part of the tibia, which resembles the margins of the glenoid 
cavity and acetabulum; for it enlarges the articulation with the 
astragalus, while it serves as a ligament to the tibia and fibula. 



ANKLE JOINT 



237 



Articulation of the Leg and Foot. 



It should be observed that the tibia and fibula are so firmly 
connected with each other below, that they may be considered 
as forming but one member of this articulation. 

The varied surfaces formed by the tibia and fibula, and by the 
astragalus, when it is contiguous to them, are invested with the 
usual apparatus of articulation. The synovial fluid is generally 
observed to be very redundant in this joint. 

A lateral ligament {internal) passes downwards from the tibia 
at the internal malleolus, and is inserted into the inside of the 
astragalus, and also into the os calcis and naviculare. Some of 
the fibres are blended with those of the sheath for the tendon of 
the flexor communis; and some of them have a radiated arrange- 
ment, in consequence of which this has been called the deltoid 
ligament. 

From the fibula three ligaments arise, spoken of collectively 
as one ligament, external lateral, (ligamentum triquetrum.) The 
middle ligament, which is strong and thick, passes downwards 
from the end of that bone, to be inserted into the outside of the 
os calcis. 

The anterior and posterior ligaments pass also from the exter- 
nal malleolus, and are inserted into the anterior and posterior 
portions of the astragalus. 

Articulation of the Astragalus and Os Calcis. 

The astragalus is attached firmly to the os calcis by very 
strong and short ligamentous fibres, which arise from the fossa 
on its under surface, and are inserted into the fossa between the 
upper articulating surfaces of the os calcis. This is called the 
interosseous. This ligament separates the posterior articulations 
of the astragalus and os calcis from the anterior. The posterior 
articulation has a synovial membrane exclusively appropriated 
to it. The anterior articulation is supplied by an extension of 
the membrane which invests the articulating surfaces of the as- 
tragalus and naviculare. 

The connexion of the astragalus, with the os calcis is sup- 



2SS ARTICULATION OF THE TARSAL BONES. 

ported by the lateral ligaments of the ankle joint, and also by 
many irregular ligamentous fibres. 

Articulation of the Astragalus ivith the Os JVaviculare. 

This articulation appears calculated for considerable motion 
as well from the form of the two surfaces concerned in it, as the 
perfect state of their articulating investments. Their motions 
are restrained to a certain degree, by ligaments, which are situ- 
ated on the upper and internal surfaces of the foot. 

— On the upper surface of the foot, is a thin broad ligament 
formed of parallel and oblique fibres, stretched from the upper 
and inner face of the astragalus to the upper surface of the sca- 
phoides or naviculare ; some of the fibres extend even to the 
cuneiforme bones. 

— On the under surface of the foot, these bones are connected 
by two ligaments, calcaneo-scaphoid internum, and externum. 
— The internal arises from the inner margin of the lesser apo- 
physis of the os calcis, and runs obliquely forwards and inwards, 
to be inserted on the inner and under surface of the os navicu- 
lare. It is a strong ligament, and contributes much to the pre- 
servation of the arched form of the foot. On its under surface 
is a trochlea for the tendons of the flexor pollicis and flexor longus 
digitorum. Below it is also in contact with the tendon of the 
tibialus posticis, and above with the head of the astragalus, 
which it in part supports. 

— The external is at the outer side of the last; it arises from the 
under surface of the greater apophysis of the os calcis, and is 
inserted upon the under internal surface of the os naviculare. — 

The ligaments which pass from the anterior internal extremity of the os 
calcis to the os naviculare, and support the head of the astragalus, ought 
to be observed with attention during the examination of this joint. 

Articulation of the Os Calcis and Cuboides. 

The articulating surfaces of this joint are arranged in the 
usual manner. 

There are two additional ligaments : one placed on the upper, 
and the other on the under surfaces of the bones. The upper 



ARTICULATION OF THE 08 CALCIS AND CUBOIDES. 



239 



ligament is thin; but the under ligament is one of the strongest 
of the foot ; and its fibres are blended with those which form 
the sheath for the tendon of the peroneus longus, as it passes 
along the groove in the cuboides. 

— These, ligaments are called the superior and inferior catca- 
neo-cuboid. 

— The superior passes from the upper anterior surface of the os 
calcis to the adjoining surface of the os cuboides. 
— The inferior is the strongest ligament of the foot. It arises 
from the inferior back part of the os calcis, and is inserted upon 
the oblique ridge which traverses the under part of the os cu- 
boides. A great part of the fibres of this ligament, pass beyond 
the ridge and are inserted in fasciculi upon the basis of the third 
and fourth metatarsal bones. These subtend the groove, in 
which passes the tendon of the peroneus longus muscle. 
— The other bones of the foot are united in general by dorsal and 
plantar ligaments like the corresponding bones of the hand. — 



240 PARTICULAR LIGAMENTS 



CHAPTER VI. 

OF PARTICULAR LIGAMENTS, AND OF THE SITUATION OF THE 
INDIVIDUAL BURS^E MUCOSAE. 

Enumeration of the most important Ligaments, which have not been described. 

Ligaments proper to the Scapula. 

The triangular ligament (ligamenlum coraco-acromialis) arises 
broad from the external surface of the coracoid process, and be- 
comes narrower where it is fixed to the posterior margin of the 
acromion. It confines the tendon of the supra-spinatus muscle, 
and assists in protecting the upper and inner part of the joint of 
the humerus. 

The posterior ligament of the scapula (coracoid) is sometimes 
double, and is stretched across the semilunar notch of the 
scapula, forming that notch into one or two holes for the pas- 
sage of the superior posterior scapulary vessels and nerves. It 
also gives rise to part of the omo-hyoideus muscle. 

The Interosseous Ligament of the Forearm, 

Extends between the sharp ridges of the radius and ulna, fill- 
ing up the greater part of the space between these two bones, 
and is composed of small fasciculi, or fibrous slips, which run 
obliquely downwards and inwards. Two or three of these, 
however, go in the opposite direction, and one of them, termed 
oblique ligament and chorda transversalis cubiti, is stretched be- 
tween the tubercle of the ulna and under part of the tubercle of 
the radius. In different parts of the ligament there are perfora- 
tions for the passage of blood-vessels from the fore to the back 
part of the bone, and a large opening is found at the upper part 



LIGAMENTS OP THE HAND. 241 

of it which is filled up by muscles. It prevents the radius from 
rolling too much outwards, and furnishes a commodious attach- 
ment for muscles. 

Ligaments retaining the Tendons of the Muscles of the Hand 
and Fingers in their proper positions. 

The anterior annular ligament of the wrist is stretched across 
from the projecting points of the pisiform and unciform bones, 
to the os scaphoides and trapezium, and forms an arch which 
covers and preserves in their places the tendons of the flexor 
muscles of the fingers. 

The vaginal ligaments of the flexor tendons are five mem- 
branes, connecting the tendons of the sublimis, first to each 
other, and then to those of the profundis ; forming, at the same 
time, bursse mucosae which surround the tendons. 

The vaginal or crucial ligaments of the phalanges arise from 
the ridges on the concave side of the phalanges, and run over 
the tendons of the flexor muscles of the fingers. Upon the body 
of the phalanges, they are thick and strong, to bind down the 
tendons, but over the joints they are thin, and have, in some 
parts, a crucial appearance, to allow the ready motion of the 
joints. 

The accessary ligaments of the flexor tendons of the fingers 
are small tendinous fraena, arising from the first and second 
phalanges of the fingers. They run obliquely forwards within 
the vaginal ligaments, terminate in the tendons of the two flexor 
muscles of the fingers, and assist in keeping them in their places. 

The posterior annular ligament of the wrist is part of the 
aponeurosis of the forearm, extending across the back of the 
wrist, from the extremity of the ulna and os pisiforme to the 
extremity of the radius. It is connected with the small annular 
ligaments which tie down the tendons of the extensores ossis 
metacarpi et primi internodii pollicis, and the extensor carpi 
ulnaris. 

The vaginal ligaments aJhere to the last mentioned, and serve 
as sheaths and bursas mucosae to the extensor tendons of the 
hand and fingers. 

vol. i. 21 



242 



LIGAMENTS OF THE STERNUM. 



The transverse ligaments, of the extensor tendons, are apo- 
neurotic slips running between the tendons, near the heads of 
the metacarpal bones, and retaining them in their places. 

Ligaments on the Anterior part of the Thorax. 

The membrane proper to the sternum is a firm expansion, com- 
posed of tendinous fibres running in different directions, and 
covering the anterior and posterior surfaces of the bone, being 
confounded with the periosteum. 

The ligaments of the cartilago ensiformis are part of the pro- 
per membrane of the sternum, divided into strong bands, which 
run obliquely from the under and forepart of the second bone of 
the sternum, and from the cartilages of the seventh pair of ribs, 
to be fixed to the cartilago ensiformis. The ligaments covering 
the sternum serve considerably to strengthen that bone. 

There are also thin tendinous expansions which run over the 
intercostal muscles at the fore part of the thorax, and connect 
the cartilages of the ribs to each other. 

Ligaments of the Bones of the Pelvis. 

The two transverse ligaments of the Pelvis (ilio-lumbar) arise 
from the posterior part of the spine of the os ilium, and run 
transversely. The superior is fixed to the transverse process of 
the last vertebra of the loins ; the inferior to the first transverse 
process of the os sacrum. 

The sacro-spinous ligaments (Jig. sacro-spinosum) arise from 
the posterior superior spinous process of the os ilium, descend 
obliquely, and are fixed to the first, third, and fourth spurious 
transverse processes of the os sacrum. 

These with the two transverse ligaments, assist in binding the 
bones together, to which they are connected. 

The two sacro-ischiatic ligaments are situated in the under and 
back part of the pelvis. They arise in common from the trans- 
verse processes of the os sacrum, and likewise from the under 
and lateral part of that bone, and from the upper part of the os 
coccygis. The first, called the large external or posterior, de- 
scends obliquely, to be fixed to the tuberosity of the os ischium. 



LIGAMENTS OF THE PELVIS. 243 

The other, called the small, internal or anterior, runs trans- 
versely to be fixed to the spinous process of the os ischium. 
These two ligaments assist in binding the bones of the pelvis, in 
supporting its contents, and in giving origin to part of its muscles. 

There are two membranous -productions which are connected 
with the large sacro-ischiatic ligament, termed its superior and 
inferior appendices. 

The superior appendix, which is tendinous, arises from the 
back part of the os ilium, and is fixed along the outer edge of 
the ligament, which it increases in breadth. 

The inferior or falciform appendix, situated within the cavity 
of the pelvis, the back part of which is connected with the middle 
of the large external ligament, and the rest of it is extended round 
the curvature of the os ischium. 

These two productions assist the large sacro-ischiatic ligament 
in furnishing a more commodious situation for, and insertion of, 
part of the gluteus maximus, and obturator internus muscles. 

Besides the sacro-spinous, and sacro-ischiatic ligaments, several 
other slips are observed upon the back of the os sacrum, which 
descend in an irregular manner, and strengthen the connexion 
between that bone and the os ilium. This constitutes the sacro- 
iliac ligament. It is also found on the anterior face of the joint, 
but there it is much thinner and weaker. 

The large holes upon the back part of the os sacrum are also 
surrounded with various ligamentous expansions, projecting from 
one tubercle to another, and giving origin to muscular fibres, 
and protection to small vessels and nerves which creep under 
them. 

A general covering is sent down from the ligaments of the os 
sacrum, which spreads over and connects the different pieces of 
the os coccygis together, allowing considerable motion, as al- 
ready mentioned, in the description of this bone. This forms 
what is called the anterior and posterior coccygeal ligaments. 

The posterior longitudinal ligaments of the os coccygis descend 
from those upon the dorsum of the os sacrum, to be fixed to the 
back part of the os coccygis. The ligaments of this bone pre- 
vent it from being pulled too much forwards by the action of the 



244 LIGAMENTS OF THE FOOT. 

coccygeus muscle, and they restore the bone to its natural situa- 
tion, after the muscle has ceased to act. 

The ligamentous cartilage, which unites the two ossa pubis so 
firmly together as to admit of no motion, excepting in the state 
of pregnancy, when it is frequently found to be so much softened 
as to yield a little in the time of delivery. 

— There are a few transverse ligamentous fibres on the front 
part of the symphysis pubis, called the anterior pubic ligament. 
— The sub, or interpubic ligament occupies the summit of the 
arch of the pubis. It is about half an inch in breadth, and passes 
from the crus of the pubis of one side to that of the other. — 

The obturator membrane, or ligament of the foramen thy- 
roideum, adheres to the margin of the foramen thyroideum, and 
fills the whole of that opening, excepting the oblique notch at its 
upper part for the passage of the obturator vessels and nerve. 
It assists in supporting the contents of the pelvis, and in giving 
origin to the obturator muscles. 

The interosseous ligament of the leg fills the space between the 
tibia and fibula like the interosseous ligament of the forearm, and 
is of a similar structure; being formed of the oblique fibres, 
and perforated in various places for the passage of vessels and 
nerves. 

At the upper part of it there is a large opening, where the 
muscles of the opposite sides are in contact ; and where vessels 
and nerves pass to the fore part of the leg. 

It serves chiefly for the origin of part of the muscles which 
belong to the foot. 

Ligaments retaining the Tendons of the Muscles of the Foot and 
Toes in their proper position. 

The annular ligament of the tarsus is a thickened part of the 
aponeurosis of the leg, splitting into superior and inferior por- 
tions, which bind down the tendons of the extensors of the toes 
upon the forepart of the ankle. 

The vaginal ligament of the tendons of the peronei muscles, 
behind the ankle is common to both, but divides at the outer 



BURS^E MUCOSA. 



245 



part of the foot, and becomes proper to each. They preserve 
the tendons in their places, and are the bursas of these tendons. 

The laciniated ligament arises from the inner ankle, and 
spreads in a radiated manner, to be fixed partly in the cellular 
substance and fat, and partly to the os calcis, at the inner side 
of the heel. It encloses the tibialis posticus and flexor digitorum 
longus. 

The vaginal ligament of the tendon of the extensor proprius 
pollicis runs in a crucial direction. 

The vaginal ligament of the tendon of the flexor longus pollicis 
surrounds this tendon in the hollow of the os calcis. 

The vaginal and crucial ligaments of the tendons of the flexors 
of the toes inclose these tendons on the surfaces of the phalanges, 
and form their bursas mucosas. 

The accessary ligaments of the flexor tendons of the toes, as in 
the fingers, arise from the phalanges, and are included in the 
sheaths of the tendons in which they terminate. 

The transverse ligaments of the extensor tendons run between 
them, and preserve them in their places behind the roots of their 
toes. 

Enumeration of the most important Bursse Mucosae. 

Those about the articulation of the Shoulder are situated, 

1. Under the clavicle, where it plays upon the coracoid pro- 
cess. 

2. Between the triangular ligament of the scapula and the 
capsular ligament of the humerus. 

3. Between the point of the coracoid process and capsular 
ligament of the humerus. 

4. Between the tendon of the subscapularis muscle and capsular 
ligament of the humerus, frequently communicating with the 
cavity of that joint. 

5. Between the origin of the coraco-brachialis and short head 
of the biceps muscles, and capsular ligament of the humerus. 

6. Between the tendon of the teres major and the os humeri, 
and upper part of the tendon of the latissimus dorsi. 

21 * 



246 BURSjE mucosae of the upper extremity. 

7. Between the tendon of the latissimus dorsi and os humeri. 

8. Between the tendon of the long head of the biceps flexor 
cubiti and the humerus. 

The bursa? marked 3 and 5 are sometimes absent. 

Near the articulation of the Elbow there are, 

1. With a peloton of fat, between the tendon of the biceps and 
tubercle of the radius. 

2. Between the tendon common to the extensor carpi radialis 
brevior, extensor digitorum communis, and round head of the 
radius. 

3. A small bursa, between the tendon of the triceps extensor 
cubiti and olecranon. 

On the Forearm and Hand are situated, 

1. A very large bursa surrounding the tendon of the flexor 
pollicis longus. 

2. Four long bursa? lining the sheaths which enclose the 
tendons of the flexors upon the fingers. 

3. Four short bursa? on the forepart of the tendons of the 
flexor digitorum sublimis in the palm of the hand. 

4. A large bursa between the tendons of the flexor pollicis 
longus, the forepart of the radius, and capsular ligament of the 
os trapezium. 

5. A large bursa between the tendons of the flexor digitorum 
profundis, and the forepart of the end of the radius, and capsular 
ligament of the wrist. 

These two last mentioned bursa? are sometimes found to communicate with 

each other. 

7. A bursa between the tendon of the flexor carpi radialis and 
os trapezium, 

8. Between the tendon of the flexor carpi ulnaris and os pisi- 
forme. 

9. Between the tendon of the extensor ossis metacarpi pollicis 
and radius. 



BURS.E MUCOSAE OF THE THIGH. 247 

10. A large bursa common to the extensores carpi radialis, 
where they cross behind the extensor ossis metacarpi pollicis. 

11. Another common to the extensores carpi radialis, where 
they cross behind the extensor secundi internodii pollicis. 

12. A third, at the insertion of the tendon of the extensor carpi 
radialis brevior. 

13. A bursa for the tendon of the extensor secundi internodii 
pollicis, which communicates with the second bursa common to 
the extensores carpi radiales. 

14. Another bursa between the tendon of the extensor secundi 
internodii pollicis and metacarpal bone of the thumb. 

15. A bursa between the tendons of the extensor of the fore, 
middle, and ring fingers, and ligament of the wrist. 

16. For the tendons of the extensor of the little finger. 

17. Between the tendon of the extensor carpi ulnaris and liga- 
ment of the wrist. 

Upon the Pelvis and upper part of the Thigh there are, 

1. A very large bursa between the iliacus internus psoas mag- 
nus muscle, and capsular ligament of the thigh bone. 

2. One between the tendon of the pectinalis muscle of the thigh 
bone. 

3. Between the gluteus medius and trochanter major, and before 
the insertion of the tendon of the pyriformis. 

4. Between the tendon of the gluteus minimis and trochanter 
major. 

5. Between the gluteus maximus and vastus externus. 

6. Between the gluteus medius and pyriformis. 

7. Between the obturator internus and os ischium. 

8. An oblong bursa continued a considerable way between the 
obturator internus, gemini, and capsular ligament of the thigh 
bone. 

9. A small bursa at the head of the semimembranosus and 
biceps flexor cruris. 

10. Between the origin of the semitendinosus and that of the 
two former muscles. 



248 BURSyE MUCOSA OF THE KNEE AND ANKLE. 

11. A large bursa between the tendon of the gluteus maximus 
and root of the trochanter major. 

12. Two small bursae between the tendon of the gluteus 
maximus and thigh bone. 

About the Joint of the Knee are, 

1. A large bursa behind the tendon of the extensors of the leg, 
frequently found to communicate with the cavity of the knee 
joint. 

2. Behind the ligament which joins the patella to the tibia, in 
the upper part of the cavity of which a fatty substance projects. 

3. Between the tendons of the sartorius, gracilis, semitendi- 
nosus, and tibia. 

4. Between the tendons of the semimembranosus and gemellus, 
and ligament of the knee. This bursa contains a small one 
within it, from which a passage leads into the cavity of the joint 
of the knee. 

5. Between the tendon of the semimembranosus and the lateral 
internal ligament of the knee, from which also there is a passage 
leading into the joint of the knee. 

6. Under the popliteus muscle, likewise communicating with 
the cavity of the knee joint. 

About the Ankle there are, 

1. A bursa between the tendon of the tibialis anticus, and under 
part of the tibia and ligament of the ankle. 

2. Between the tendon of the extensor proprius pollicis pedis, 
and the tibia and capsular ligament of the ankle. 

3. Between the tendons of the extensor digitorum longus, and 
ligament of the ankle. 

4. Common to the tendons of the peronei muscles. 

5. Proper to the tendon of the peroneus brevis. 

6. Between the tendon achillis and os calcis, into the cavity of 
which a peloton or mass of fat projects. 

7- Between the os calcis and flexor pollicis longus. 
8. Between the flexor digitorum longus and the tibia and os 
calcis. 



BUKSjE MUCOSAE OF THE FOOT. 249 

9. A bursa between the tendon of the tibialis posticus and the 
tibia and astragalus. 

On the Sole of the Foot are also, 

1. A second bursa for the tendon of the peroneus longus, with 
an oblong peloton of fat within it. 

2. One common to the tendon of the flexor pollicis longus, and 
that of the flexor digitorum profundus, at the upper end of which 
a fatty substance projects. 

3. Another for the tendon of the tibialis posticus. 

4. Several for the tendons of the flexors of the toes. 



251 



ANATOMICAL PLATES. 



EXPLANATION OF THE PLATES OF OSTEOLOGY. 



Plate V. 

Fig. 1. A Posterior View of the Sternum and Clavicles, with the liga- 
ment connecting the clavicles to each other. 

a, The posterior surface of the sternum, b b, The broken end of the cla- 
vicle, cccc, The tubercles near the extremity of each clavicle, d, The 
ligament connecting the clavicles. 

Fig. 2. A Fore View of the Left Scapula, and a half of the Clavicle, with 
their Ligaments. 

a, The spine of the scapula, b, The acromion, c, The inferior angle, 
d, Inferior costa. e, Cervix, f, Glenoid cavity, covered with cartilages for 
the arm bone, g g, The capsular ligament of the joint, h, Coracoid pro- 
cess, i, The broken end of the clavicle, k, Its extremity joined to the 
acromion. 1, A ligament coming out single from the acromion to the cora- 
coid process, m, A ligament coming out single from the acromion, and di- 
viding into two, which are fixed to the coracoid process. 

Fig. 3. The Joint of the Elbow of the Left Arm, with the Ligaments. 

a, The os humeri, b, Its internal condyle, c c, The two prominent 
parts of its trochlea appearing through the capsular ligament, d, The 
ulna, e, The radius, f, The part of the ligament including the head of 
the radius. 

Fig. 4. The Bones of the Right Hand, with the Palm in view. 

a, The radius, b, The ulna, c, The scaphoid bone of the carpus, d, 
The os lunare. e, The os cuneiforme. f, The os pisiforme. g, Trape- 
zium, h, Trapezoides. i, Magnum, k, Unciforme. 1, The four meta- 
carpal bones of the fingers, m, The first phalanx, n, The second phalanx, 
o, The third phalanx, p, The metacarpal bone of the thumb, q. The first 
joint, r, The second joint. 

Fig. 5. The Posterior View of the Bones of the Left Hand. 

The explication of Fig. 4, serves for this figure ; the same letters point- 
ing out the same bones, though in a different view. 



252 EXPLANATION OF THE PLATES OF OSTEOLOGY. 

Fig. 6. The Upper Extremity of the Tibia, with the Semilunar Cartilages 
of the Joint of the Knee, and some Ligaments. 

a, The strong ligament which connects the patella to the tubercle of the 
tibia, b b, The parts of the extremity of the tibia covered with cartilage, 
which appear within the semilunar cartilages, c c, The semilunar carti- 
lages, d, The two parts of what is called the cross ligament. 

Fig. 7. The Posterior View of the Joint of the Right Knee. 

a, The os femoris cut. b, Its internal condyle, c, Its external condyle, 
d, The back part of the tibia, e, The superior extremity of the fibula, f, 
The edge of the internal semilunar cartilage, g, An oblique ligament, h, 
A large perpendicular ligament, i, A ligament connecting the femur and 
fibula. 

Fig. 8. The Anterior View of the Joint of the Right Knee. 

b, The internal condyle, c, Its external condyle, d, The part of the 
os femoris, which the patella moves, e, A perpendicular ligament, ff, The 
two parts of the crucial ligaments, g g, The edges of the two movable 
semilunar cartilages, h, The tibia, i, The strong ligament of the patella, 
k, The back part of it where the fat has been dissected away. 1, The ex- 
ternal depression, m, The internal one. n, The cut tibia. 

Fig. 9. A View of the Inferior part of the Bones of the Right Foot 

a, The great knob of the os calcis. b, A prominence on its outside, c, 
The hollow for tendons, nerves and blood-vessels, d, The anterior extre- 
mity of the os calcis. e, Part of the astragalus, f, Its head covered with 
cartilage, g, The internal prominence of the os naviculare. h, The os cu- 
boides. i, The os cuneiforme internum, k, Medium. 1, Externum, m, 
The metatarsal bones of the four lesser toes, n, The first. o,'The second, 
p, The third phalanx of the four lesser toes, q, The metatarsal bones of 
the great toe. r, Its first — s, Its second joint. 

Fig. 10. The Inferior Surface of the two large Sesamoid Bones, at the 
first Joint of the Great Toe. 

Fig. 11. The Superior View of the Bones of the Right Foot. 

a, b, as in Fig. 9. c, The superior head of the astragalus, d, &c, as 
in Fig. 9. 

Fig. 12. The View of the Sole of the Foot, with its Ligaments. 

a, The great knob of the os calcis. b, The hollow for the tendons, 
nerves, and blood-vessels, c, The sheaths of the flexores pollicis and digi- 
torum longi opened, d, The strong cartilaginous ligament supporting the 
head of the astragalus, e, h, Two ligaments which unite into one, and are 
fixed to the metatarsal bone of the great toe. f, A ligament from the nob of 
the os calcis to the metatarsal bone of the little toe. g, A strong triangular 
ligament which supports the bones of the tarsus, i, The ligaments of the 
joints of the five metatarsal bones. 



EXPLANATION OF THE PLATES OF OSTEOLOGY. 



Fig. 13. 



253 



a, The head of the thigh bone of a child, b, The ligamentum ro- 
tundum connecting it to the acetabulum, c, The capsular ligament of the 
joint with its arteries injected, d, The numerous vessels of the mucilagi- 
nous gland injected. 

Fig. 14. The Back View of the Cartilages of the Larynx, with the 

Os Hyoides. 

a, The posterior part of the base of the os hyoides. b b, Its cornua. c, 
The appendix of the right side, d, A ligament sent out from the appendix 
of the left side, to the styloid process of the temporal bone, e, The union 
of the base with the left cornu. f f, The posterior sides of (g) the thyroid 
cartilage, h h, Its superior cornua. i i, Its inferior cornua. k, the cricoid 
cartilage. 1 1, The arytenoid cartilages., m, The entry into the lungs, 
named glottis, n, The epiglottis, o o, The superior cartilages of the tra- 
chea, p, Its ligamentous back part. 

Fig. 15. The Superior Concave Surface of the Sesamoid Bones at the 
first joint of the Great Toe, with their Ligaments. 

a, Three sesamoid bones, b, The ligamentous substance in which they 
are formed. 



vol. i. 22 



PART III. 
MYOLOGY. 

CHAPTER VII. 

GENERAL ANATOMY OF MUSCLES.* 

That soft, fibrous, red-coloured substance, which constitutes 
so large a proportion of the volume of the more perfect animals, 
is called Flesh or Muscle. 

By the contraction of this substance, the spontaneous motions 
of animals are produced; and, on this account the fibres which 
compose it have long been regarded with particular attention. 

Muscular fibres are not only arranged in those regular masses 
on the trunk and limbs of the body, which are so familiar to us 
by the name of muscles, but they also exist in some of the most 
important viscera, and produce the internal, as well as the exter- 
nal, motions of animals. 

— Muscles have been divided in man, and the superior ani- 
mals, into two classes. The first class consists of those which 
produce the external motions of the body, and are placed exte- 
riorly; these contract under the influence of the will, are the 
agents by which are executed the animal or voluntary functions 
which place the animal in relation with the exterior world, and 
are called the muscles of animal life, muscles of the life of rela- 
tion, voluntary muscles, etc. These form by far the largest por- 
tion of the whole mass, and are attached in general, by one or 
both extremities to the skeleton. They are solid, that is, have 
no cavity in their interior, and vary much in their size. The 
second class consists of those placed in the interior of the 

" Muscles were first named according to their figure and situation, in 1587, by 
Jacques Dubois, surnamed Sylvius, a member of the Faculty of Medicine in 
Paris.- — h. 



256 GENERAL ANATOMY OF MUSCLES. 

body, and which effect the movements requisite in the various 
processes of nutrition and generation. These are not under 
the control of the will, and are called the muscles of organic life, 
muscles of the life of nutrition, involuntary muscles, etc. They 
are generally membraniforme, and assist in forming the hollow 
organs, as in the heart, digestive canal, uterus and bladder. 
With the exception of those of the heart, the fibres of this class 
of muscles are of a pale colour, and some entirely colourless. 
A few of the muscles of animal life, as those of the ears and 
some of those of the face, are likewise faintly coloured, and 
are considered by Isenflam,* as existing even in the adult in a 
state of rudimental developement, as their colour and functions 
are found much more fully manifested in some quadrupeds.f 
— The muscles in the inferior grades of animals appear to exist 
in a rudimental condition, and become more and more numerous, 
and of a colour more and more red, generally, as we advance 
upwards from the zero point of the animal scale. In the deve- 
lopement of the human foetus they seem to undergo analogous 
changes. 

— They present themselves during the three first months of 
foetal life, as gelatinous or viscous masses, very slightly tinged 
with yellow, and with thin tendons, according to Isenflam, already 
apparent in the flexors and extensors of the fingers and toes. 
— At the end of the fourth or fifth month, the muscles present a 
reddish aspect, and at the period of birth, though they may be 
readily dissected from each other, they are very soft, and of 
a colour much less deep than those of the adult. — 

Muscular fibres are connected to each other by cellular mem- 
brane. This membrane surrounds each muscle ; and its various 
lamina, gradually diminishing in thickness, pass between the dif- 

* Anatomische Untersuchungen, by H. F. Isenflam, Professor at the University 
of Dorpat. 

t This physiological division of the muscles into two classes, after Bichat, is 
eminently useful to the student, in enabling him to simplify and generalise his 
studies of the muscular system ; one class is not, however, wholly separate from 
the other. Between, is interposed another subdivision of muscles, called the Re- 
spiratory of Sir C. Bell, Excito-motory of Marshal Hall, Muller, and Grainger. — p. 



GENERAL AX ATOMY OF MUSCLES. 957 

ferent bundles of fibres, and the different fibres of which each 
muscle is composed. 

The fibres of muscles, when examined with magnifying 
glasses, appear to be composed of fibrillar still smaller; and it 
has been supposed that this division of them extended beyond 
our powers of vision, even when assisted by microscopes : but so 
many errors have occurred in microscopical observations of very 
minute objects, and so much difference exists between the reports 
of different observers, that the subject at this time does not in- 
terest many persons; and very little attention is paid, by the 
anatomists and physiologists of the present day, to the opinions 
of those observers who supposed they had ascertained the struc- 
ture of the ultimate fibrillar 

— The cellular or reticular membrane investing the whole 
muscle, is called the muscular sheath. It is formed round every 
muscle of the body, but varies much in different places in regard 
to thickness and strength. Each of the many fasciculi, or 
bundles of fibres, (lacerti,) of which every muscle is obviously 
composed, is surrounded in like manner by processes sent inwards 
from the sheath, and is a perfect, though diminutive, representa- 
tive of the entire muscle. 

— This secondary sheath surrounding the fasciculi, sends pro- 
cesses likewise inwards, and invests and separates the individual 
fibres of which each fasciculus is formed. These fibres themselves 
are again susceptible of subdivision into what are called the ulti- 
mate muscular filaments, between which, it is probable, though not 
susceptible of demonstration, the elementary particles of cellular 
tissue likewise pass. In the muscles of organic life, the cellular 
tissue is less abundant, but more dense than in those of animal 
life. In some parts, especially in the digestive canal it is so 
dense and resistant as to represent a sort of ligamentous tissue, 
and give attachment to muscular fibres. 

— The entire muscle thus appears naturally susceptible of three 
subdivisions. 1st. Into fasciculi, or bundles of fibres. Theso 
are the minutest subdivisions which can be made with the naked 
eve, without resort to boiling or other mechanical means. These 
are themselves collected into bundles, by septa which pass in 

22* 



258 STRUCTURE OF MUSCULAR FIBRES. 

from the general sheath of the muscles, but which are easily un- 
ravelled by a little dissection ; so that what is at first sight mis- 
taken by the student for a fasciculus, is in reality but a bundle 
of fasciculi. The size of the ultimate fasciculus, varies in the 
different muscles of the body, and occasionally in the same mus- 
cle, according to the number of fibres of which it is composed. 
2d. Into fibres. These are rendered very apparent by boiling, as 
seen daily in culinary preparations, by which the muscular fibre 
is swoln, while the cellular envelope, at the same time softened 
and reduced to a gelatinous pulp, is readily burst. These fibres 
also vary in their thickness, some having a diameter three or 
four times as great as that of others, depending upon the num- 
ber of elementary filaments of which it is composed. 3d. Into 
the elementary, or ultimate muscular filament. These are 
wholly microscopical, are uniform in their diameter in all 
muscles, and vary considerably in the numbers taken to consti- 
tute the muscular fibres of different size.* Each of the muscu- 
lar fibres, and also, each of the ultimate filaments, according to 
Prochaska and Rudolphi, extend the whole length of the fleshy 
part of the muscles, differing entirely in this respect from the ul- 
timate structure of the bones. 

— Anatomists do not agree in regard to the diameter assigned 
the ultimate muscular filament, and from its microscopical diminu- 
tiveness any measurement can be considered as little more than 
an approximation. They have been examined by Hook, Lew- 
enhceck, Dehayde, Muys, and more recently still by Prochaska 
and others. According to Prochaska, they are generally straight 
and parallel with each other, flattened or prismatic, and of a 
diameter one-fifth of that of the red globules of blood. Auten- 
reith supposed them equal to one-third of the diameter. Prevost 
and Dumas found them by their measurement, y^TT-th part of an 
inch in diameter, five or six times smaller than the red globules 
of the blood, and nearly equal, as Miiller also has asserted, to 
the diameter of the chyle globules, or to the central nuclei of 
the red globules of blood, which may be considered the most 
minute compound constituents of the economy. 
— Much of this discordance of opinion, is probably owing to 

* Meckel, torn. i. p. 378. 



STRUCTURE OF MUSCULAR FIBRES. 259 

the examinations not having always been practised upon single 
and well isolated filaments. From more recent observations by- 
Bauer and Home, Beclard, Prevost, and Dumas, H. Cloquet, 
and H. M. Edwards, the ultimate filament may be considered 
as identical in its structure with the particles of blood deprived 
of their colouring matter, of which the central globules (nuclei) 
form the filaments by being articulated end to end, by a sort of 
delicate jelly or mucus, which is probably ihe elementary form 
of the cellular tissue.* — 

These fibrillae have been represented as simple hollow tubes, 
as a series of globular vesicles, as continuations of arteries, as 
termination of nerves, as structures of rhomboidal bodies, and 
finally, as cellular.f 

It is supposed by one of the latest observers, who appears to 
be entitled to great attention,;]: that the muscular fibres are not 
thus minutely divided : that a single fibre, when separated from 
the adhering extraneous substances, and viewed in a powerful 
microscope, is a solid cylinder, formed of a pulpy substance, ir- 
regularly granulated, and covered by a portion of the reticular 
membrane. 

— The opinions of Sir A. Carlysle, are not at the present time, 
deemed of much weight in anatomy ; subsequent researches 
having shown them to be full of empty and reckless speculation. 
Among those who consider the muscular fibre as hollow, are 
Sink and Mascagni ; the latter considered it as formed of little 
cylinders, the walls of which are composed of absorbent vessels 
and filled with a glutinous substance. More recently, Raspail 
(Chimie Organique) has adopted a view which appears a modifi- 
cation of that of Mascagni. He considers each fibre formed of 
a bundle of cylinders, the cylinders made up of elongated vesi- 
cles, attached end to end, and having a spiral arrangement. — 

* For a more full and interesting' account of these microscopical investigations, 
see Human Physiology, fourth edition, by R. Dunglison, M. D., Professor of 
the Institutes of Medicine and Medical Jurisprudence in Jefferson Medical Col- 
lege, &c. &c. Phila. 1838.— r. 

t A statement of these descriptions, with reference to the publications in which 
they arc contained, may be seen in the Elementa Physiologife of Haller, vol. iv. 

| Carlysle, in the Croonian Lecture, London Philosophical Transactions, 1805, 
Part I. 



2(50 VASCULARITY OF MUSCLES. 

The connexion of these fibres, with the blood-vessels and nerves, 
is an important circumstance in the structure of muscles. 

The arteries of muscles are very numerous; and they ramify 
minutely. They are accompanied by veins; and it appears, by 
the successful labours of Ruysch, that when these arteries are 
fullv injected, they not only communicate with the veins, but 
also pour out some of their contents in a dew-like effusion in the 
muscle.* 

— With the exception of some of the viscera, as the lungs and 
kidneys, there are few organs that receive as much blood as the 
muscles. 

— The arteries that supply the muscles, enter them at all points. 
The larger trunks more generally enter at the middle of the 
muscle, and ramify towards each extremity, the branches being 
placed between the larger fasciculi or lacerti, so that the flow of 
blood, may be less impeded during muscular contraction ; mi- 
nute branches only passing into the structure of the fasciculi. 
The veins which attend the arteries, are said by Bichat to have 
few valves. The free distribution of blood to the muscles, ap- 
pears to be necessary to preserve them in a condition, healthy 
and capable of contraction. When the supply of blood is cut 
oflj by a ligature, the muscle gradually becomes paralysed, and 
does not regain its power, till it is again supplied by the anasto- 
mosing branches. 

— The colour of the muscle does not seem dependant wholly on 
the blood, but in part at least, on their own peculiar structure, as 
seen in many animals, where the flesh is white and the blood 
red ; and in the muscles of organic life in man, many of which 
are colourless, though more vascular than those of animal life. 
— The absorbent vessels exist no doubt in all the muscles, but 
they are traced with difficulty. They have been found in the 
muscles of the tongue, face and diaphragm.f — 

The blood-vessels must terminate, not in the cavities of the mus- 
cular fibres, but exterior to these fibres ; otherwise the dew-like 
effusion, would not be apparent ; and it is probable, that the red 

* See Ruysch's description of the 96tli preparation in his Thesaurus Quartns; 
and of the 35th preparation in Thesaurus Decimus. 

+ Vide Breschet, Surle Systeme Absorbantc. Paris, 1836. — r. 



COLOUR OF MUSCLES. 261 

colour, which is so general in muscles, depends upon a portion 
of blood effused from these vessels, and not contained in them ; 
for it has been observed by Bichat, that in drowned or strangled 
animals, black disoxygenated blood occupied all the vessels, 
while the florid colour of the muscles continued unchanged ; 
which could not have been the case if the colour of the muscles 
was owing to the blood in the vessels. 

That the colour of the red muscles is owing to blood, is ren- 
dered certain by the fact that this colour may be completely 
washed away while the fibrous structure of the muscle remains 
unchanged. From this also it may be inferred that the blood is 
exterior to the muscular fibre, and to the vessels likewise. 

It is said by Sabatier, that the colour will likewise be com- 
pletely removed, by injecting a large quantity of water through 
the arteries; this does not invalidate the inferences drawn from 
the other facts ; for the water effused from the extreme branches 
of the arteries must necessarily wash away the blood which 
was previously effused from the same branches. 

The water with which muscles have been washed, appears as 
if some blood had been mixed with it; it contains albumen and 
gelatine, with some fibrine, and a peculiar extractive substance, 
as well as the red colouring matter. 

The substance of the muscle, when thus separated from the 
above mentioned matter by washing, appears to be of the same 
nature with the fibrine of the blood : and after boiling some time 
in the water, it seems, like that substance, to consist of brown 
insoluble fibres, which are brittle when dry. 

When the great function of muscles is under consideration, 
nerves appear of more importance than blood-vessels. 

The nerves appropriated to muscles of voluntary motion are 
more numerous than those appropriated to any other parts, except 
the organs of sense. They subdivide into very fine fibrillae; and 
it is the opinion of one of the latest observers, that these fibrillae 
become soft and transparent, and finally blended with the reticu- 
lar membrane which surrounds the muscular fibres. 

It ought to be noted that muscles are indued with great sensi- 



262 0F THE TENDONS. 

bility, and that the smallest puncture cannot be made in them 
without exciting pain. 

Of the Tendons. 

Thus arranged, the fibres of muscles are most generally at- 
tached to tendons, which are inserted into the bones these mus- 
cles are intended to move. They are also, in some cases, 
inserted into tendinous membranes, and other parts necessary 
to be moved; but in all such instances these parts are perfectly 
passive ; and the motion in which they are concerned is alto- 
gether produced by the contraction of the muscular fibres. 

— The tendons appear to be formed of a continuation of the 
cellular membrane which envelopes the fibres of the muscles. 
The ultimate construction of muscles was shown in page 259, 
to consist of a multitude of filaments each one composed of 
a linear series of the muscular molecules ; each of the mole- 
cules being contained in a series of cells of the cellular tissue, 
all of which are continuous with each other. The muscular 
matter is found in general only in the middle part of the cellular 
tissue; the latter is continued on at each extremity of the mus- 
cle, where it is compacted into a solid mass, presents a liga- 
mentous appearance, and constitutes the tendons, or cords by 
which the muscles are attached to the periosteum covering the 
bone. Hence the tendons are continuous with, and must obey 
to a certain extent the contraction of every muscular fibre. 
— The tendons exist under a great variety of forms : most ge- 
nerally round or cylindrical, sometimes flat, radiated, bifurcated, 
etc., but are always susceptible, by a little dissection, of being un- 
folded into a membrane. They have little vascularity, no sensa- 
tion in a healthy state, no nerves having ever been traced into 
them, and are of a strength surpassing that of almost any other 
substance of equal size. They have a great affinity for phos- 
phate of lime especially in old persons, in whom it is not very 
unusual to find them ossified ; and very frequently at all stages 
of life, we find developed in their substance sesamoid bones. 
— The muscles are often from inanition or want of use much 
wasted away, the red muscular matter disappearing from the 



OF THE TENDONS. 



263 



cells in which its particles are contained. The cells, however, 
remaining, if the system regains its vigour, or the muscles are 
brought into use, they are filled anew with the muscular mole- 
cules, and the muscle is restored to its former size, and its con- 
traction will take place with its usual force. 
— From this mode of formation, it is evident that there must be 
an exact relation between the force of the muscle, and the 
strength of its tendons, even when the muscle is most fully de- 
veloped. The size and power of the muscle is much dependent 
upon its use. 

— The muscles of the legs in dancers, of the arms in black- 
smiths, of the shoulders and back in porters, all obtain an increase 
of bulk from use, which still better fits them for the duties they 
have to perform. This is strongly exemplified in birds; the breast 
bone and muscles attached to it being more strongly developed 
than those of the legs, in birds which are much upon the wing; 
the reverse taking place in the ostrich, cassowary and penguin, 
which employ the wings only as aids to the feet. — 

Notwithstanding the great attention that has been paid to this 
important operation of muscular fibres, the immediate cause is 
yet unknown. 

Muscular motion takes place under the following different cir- 
cumstances: — 

1st. When irritation or stimulus is applied directly to the mus- 
cular fibre. 

2d. When irritation is applied to a nerve connected with the 
muscles. 

3d. When it is induced by volition. 

There are several causes of muscular action which cannot be 
arranged under either of these heads, although it is probable 
they are not essentially different; such as the motions of cough- 
ing and sneezing, of yawning, &c. 

The immediate irritation of a muscle is effected by every me- 
chanical process, which punctures, divides, lacerates or extends 
its fibres ; by acrid, and, perhaps, other chemical and peculiar 
qualities of the substance applied to the muscles ; by a sudden 
change of temperature ; and by electricity and galvanism. 



264 



PHENOMENA OP MUSCULAR MOTION. 



No satisfactory explanation has yet been made of the manner 
in which muscular contraction is excited, either by the above- 
mentioned agents, by irritation applied to a nerve, or by volition. 

When a muscular fibre begins to contract, there is often the 
appearance of a slight tremor in it. It becomes hard and rigid: 
its length diminishes, and its diameter increases. If a muscle 
makes an effort to contract, when the parts to which its extremi- 
ties are attached are prevented from moving towards each other, 
so that contraction cannot take place, the muscle will become 
hard and rigid notwithstanding. 

— This tremor of the fibres, is called fibrillary agitation, (agi- 
tation fibrillaire,) and is heard when a stethoscope is applied 
over the belly of a muscle during its contraction, or when the 
end of the finger is introduced into the auditory meatus. During 
the contraction of a muscle there is no change in its colour, nor 
any increase in the amount of blood thrown into it by the arte- 
ries as was once supposed. 

— With the aid of the microscope it is easy to distinguish the 
manner in which the contraction of a muscle is effected. Fig. 
12, exhibits a magnified view of the 
muscular fibres in a state of relaxation. 
When they contract they form suddenly 
a number of zigzag flexions, or angular 
undulations, opposite each other, as seen 
in Fig. 13, page 265, according to 
the observation of Edwards,f Prevost, 
and Dumas. By repeated experiments, 
these gentlemen have determined that the 
flexures of each fibre take place at 
certain determined points, and nowhere 
else. These points are precisely at the 
places where the nerve a, the brink of 



Fig. 12.* 



1 1 V' 'Hq 

III 
JiMIfl 



Hi fli 






* a, Nerve, b b, Fasciculi of muscular fibres which are straight and parallel, c, 
Nervous filament which separates from the nerve a, and crosses at right angles, 
and at regular distances, the muscular fasciculi. 

t Elements de Zoologie, etc., par M. H. Edwards. Paris, 1838. 



/// 'ill 



wemm 

:\rafra~ 



it'JafcfrJ 



PHENOMENA OF MUSCULAR MOTION. 265 

which runs parallel with the muscular fibres, Fig. 13.* 

sends off its filaments to traverse the muscu- j a 

lar fibres, at the spot where the angles of the 
undulations are formed. These nervous fila- 
ments after having continued the course for c 
some time, are reflected in the form of loops, 
and return towards the brain, so as to consti- 
tute with that organ a continuous circle. Du- c 
ring the contraction of the muscle its extremi- 
ties approach, for though the absolute length 
of the fibre remains the same, the distance i> < a 

between its extremities is diminished by the undulations. The 
will transmitted through the nerves is the usual stimulus, which 
excites the voluntary muscles to contraction. Galvanic elec- 
tricity, or disease of nervous centres will produce the same 
result; that of the involuntary muscles, usually results from the 
impression made upon the organs, as by food in the stomach, 
blood in the heart, urine in the bladder, &c. — 

It has often been inquired whether the whole bulk of a muscle 
is diminished or increased by its contraction. It now seems 
generally agreed that the bulk is not increased ; and, if there is 
any real diminution of the fibre itself, it is very small indeed. 

The irritability of the muscular fibre, or its power of contract- 
ing upon the application of stimulus, exists in a greater degree 
in some muscular parts than others. It is suspended by the ap- 
plication of narcotic substances; and it remains, in many cases, 
a short time after the vital functions have ceased. 

In a majority of cases a general contraction seems to take place 
in the last moments of life ; and after death the body is stiff in 
consequence of it; all the movable parts being fixed in the pre- 
cise situation in which they were when the vital motions ceased. 
The limbs being generally in a bended position at that time, if 
an attempt be made to extend them it will be very evident that 
the contracted state of the muscles impedes this extension. When 
this contraction is once overcome, the limbs continue perfectly 

* Fig. 13. The same muscle at the moment of contraction, and a b c, indicates 
the same, as in Fig. 12. 

vol. I. 23 



266 PHENOMENA OF MUSCULAR MOTION. 

flexible, and the muscles are ever after relaxed ; but the force of 
contraction is sometimes so great that it will require a consider- 
able exertion of strength to overcome it. This condition of the 
muscles, after death, although very common, is not universal: 
and some dead subjects are perfectly relaxed and flexible from 
the first cessation of the vital functions. 

The force with which muscles contract exceeds greatly their 
inanimate power of cohesion. Thus, a muscle deprived of life, 
would be completely lacerated by a weight suspended from it, 
which it could readily raise by its contraction during life. This 
force of contraction is so great, that the tendo-achillis and the 
patella have been repeatedly broken by the mere power of the 
muscles, inserted into them. 

The rapidity with which the successive contractions of the 
same parts take place is extreme ; and as a striking proof of it, 
the motions of the tongue, in rapid speaking or reading, are re- 
ferred to by physiologists. 

The extent or degree of muscular contraction, is, in some cases, 
very great. In proof of this it was stated by the second Monro, 
that crude mercury, which passes so readily through the intes- 
tines, could not be carried along any parts of them whose posi- 
tion happened to be perpendicular, (as the colon on the right 
side when we stand,) unless the circular fibres of the intestine 
contract behind it to such a degree as to close completely the 
cavity of that tube. 

An interesting question may be proposed here, — Whether the 
power of motion, as above described, is exclusively enjoyed by 
muscular fibres; whether these fibres must be supposed to exist in 
all those parts of the body which occasionally perform contraction? 

It has often been inferred, that parts were muscular because 
they were capable of contraction ; but the question above ought 
to be decided affirmatively before such inferences can be pro- 
perly made. 

The sac of the taenia hydatigena appears to be a membrane of 
a peculiar structure, very different from muscle; yet it is as 
capable of contracting as if it were perfectly muscular.* 

* See the Croonian Lecture by Mr. Home ; London Philosophical Transactions 
for 1795, Part I. page 204. 



PHENOMENA OF MUSCULAR MOTION. og* 

The membrane of the urethra does not appear to be muscular 
in its structure ; and yet it has been seen to protrude a bougie, 
which had passed near to the neck of the bladder, in a way that 
indicated regular successive contraction, throughout its whole 
extent. 

The question above stated, may, therefore, be considered as 
not yet decided affirmatively. 

Muscular fibres are situated very differently in different parts. 
They compose almost the whole substance of the heart, which 
is therefore called a hollow muscle. They also form one of the 
coats of the stomach and intestines, and of the urinary bladder. 

In the muscles on the trunk and limbs, their arrangement is 
very various, being rectilinear, penniform, radiated, &c. 

There are a great many short fibres, with an oblique direc- 
tion, in some muscles of small volume, which have therefore 
great power and little motion, as in the semimembranosus. 

— Contraction, though the only power that muscles appear 
to exercise, is found likewise existing to some extent, in other 
tissues of the body, where some effort and resistance is required 
in the performance of their functions, without the necessity of 
that perfect antagonism of action which muscles usually establish. 
There appears, in fact, to be a regular gradation in the changes 
of the condition of the muscular fibre. The muscles of animal 
life in man are the most fully developed, most highly coloured, 
and enjoy to the fullest extent, the powers of contraction. Their 
only vital action is that of contraction, which has been before 
explained, (see page 264,) which causes their ends to approach 
each other, by moving one or the other of the bones, to which 
the two ends of the muscles are attached. One of the bones is 
usually more readily moved than the other, and that is the action 
of the muscle as usually set down in books. But the student 
will do well to impress upon his mind, that that is not the only 
movement which the muscle can effect, and that if the part 
which it usually moves, becomes, from some adventitious cause 
more solidly fixed than the other, as from a weight attached to 
it, or the opposing action of other muscles, the contraction of 
the muscles will produce a movement of the part, at which its 



26g ANTAGONISM OF MUSCLES. 

other extremity is inserted. In this way the action of muscles 
is beautifully varied, and very complicated and useful move- 
ments are produced in the body, by what seems a very simple 
arrangement of the muscles. Thus the action of the great pec- 
toral and latissimus dorsi muscles is usually to pull down the 
arms when they have been elevated by other muscles. But if 
the arms are thrown upwards, and the hands grasp some place 
above, as the limbs of a tree, they then raise the body upwards 
towards the arms, and thus become the muscles used in climbing. 
— In violent dyspnoea, arising from spasmodic croup, asthma, or 
other causes, the arms are frequently drawn upwards so firmly 
by the muscles at the top of the shoulders, that the pectoralis 
major and latissimus dorsi cannot pull them down. When they 
contract, therefore, their extremities are made to approach by 
raising the ribs to which they are in part attached, and thus be- 
come muscles of forced inspiration. 

— The muscles of animal life are arranged, so that each one has 
its antagonist, or opposing muscle. Thus, there are flexors to 
bend the limbs, and extensors to straighten them, supinators and 
pronators, elevators and depressors. The muscles, which are 
very numerous, and like the bones are variously estimated, from 
368 by Chaussier, to 400 or more by other writers, and produc- 
ing by their single action a great variety of movements, are yet 
combined together in pairs or much larger numbers, so as to 
extend beyond computation the variety of movements they are 
capable of producing. Thus the two muscles already named, 
one of which, when acting separately, draws the arm usually 
downwards and forwards, the other downwards and back- 
wards, when combined together draw it down in the diagonal 
or middle line. 

— The antagonism of the muscles is dependent upon their alter- 
nate contraction : the shortened or contracted muscle, is re- 
stored to its former length chiefly by the contraction of its anta- 
gonist, but partly also by the resiliency of the cellular tissue in 
its composition. They are also capable of acting to a certain 
extent in unison, and thus give firmness and steadiness to the 
limbs or other parts, and hold them in a fixed direction, as 



MODE OF INSERTION. 269 

occurs habitually in walking or standing, or pointing with the 
arm. 

— The antagonising muscles do not appear to be equally ba- 
lanced in regard to power ; thus the most usual attitudes, in 
sleep, palsy or tetanus, where the muscles are uninfluenced by 
the will, is the extended position for the back, flexion to the arm 
in general, pronation to the fore arm, flexion to the lower ex- 
tremities and adduction to the foot. This is not dependent upon 
a difference in length, as was supposed by Borelli, but, according 
to Beclard, chiefly upon a difference in size, and the relative ad- 
vantages of insertion upon the bones. 

— Muscles have their tendons attached to the bones, in a manner 
to give them the least mechanical power, but to effect the greatest 
rapidity of motion ; for, as has been observed by Archdeacon 
Paley, it is of far greater importance to man, to be able to carry 
his arm quickly to his head, than to raise several hundred weight 
more than he is now able to do : the two qualities could not well 
exist together. All that could be done to increase the power, with- 
out impairing the symmetry of the body, or diminishing the celerity 
of its movements, has been accomplished in endowing the mus- 
cles, with an extraordinary force of contraction, at least ten fold 
as great as the student would at first suppose it. The muscles 
are nearly all levers of the third order. 

— The force with which a muscle contracts, depends upon its 
volume and the energy of the will, as well as some other circum- 
stances. But the effect produced by the contraction will depend 
in a great measure upon the manner in which it is inserted upon 
the bone on which it acts. 

— Thus, all things being the same, the effect of the contraction 
will be the greater, in proportion as 
the muscle is less obliquely con- 
nected with the bone. Thus of the 
muscle m, figure 14, the force of 
which we suppose equal to 10, is '' 
fixed perpendicularly to the bone /, 
the extremity of which a, is mova- 
ble upon the fulcrum point r, it will 
have to overcome only the weight * 

23* 




270 FORCE OF MUSCULAR CONTRACTION. 

of the bone, and will carry it from the position a b, into the 
direction of the line a c. But if this muscle acted obliquely upon 
the bone in the direction of the line n b, it would then tend to 
carry it in the direction of the line b n, and consequently to force 
it against the fixed articular surface r. This latter being a fixed 
surface, the bone can only turn upon the point r, as upon a pivot, 
and the contraction of the muscle n, having the same force as 
the muscle m, would only be able to carry the bone in the direc- 
tion a d, and would require a force equal to 40, or four times 
that of m, to raise it in the direction of the line a c. 
— In the animal economy the muscles are inserted most usually, 
very obliquely, and consequently in a manner little favourable to 
the intensity of the result of their contraction. There is never- 
theless a very happy contrivance, which tends to diminish the 
obliquity of their insertions, without marring the usefulness or 
symmetry of the limbs. It is the articular swellings at the ex- 
tremities of the bones, which contribute also to the stability of 
the joints. 

— The tendon i of the muscles m, Fig. 15, are inserted in 
general immediately below the articulation, 
upon the mobile bone o, in a direction more Fig. 15. 

approaching the perpendicular, thus making 
the head of the bone a sort of pulley over m 
which it acts, by which the effect of the 
contraction is considerably increased. ] 

— A more striking instance is met with in 
the deltoid muscle. Baron Haller, has made an interesting cal- 
culation of the absolute force required to be exerted by the del- 
toid muscle, in order to raise a weight of 60 pounds at the elbow, 
reckoning the weight of the arm, at 5 pounds of this. Its inser- 
tion is at an angle of 10 degrees upon the humerus, and at about 
one-third of the distance between the shoulder and elbow. The 
force requisite to raise a weight is exactly in the proportion, of 
the distance which the weight from the fulcrum bears to that of 
the power from the fulcrum. Thus, from the disadvantage of 
insertion, the force requisite to be exercised there is three times 
as great as it would be if inserted at the elbow ; therefore the 



MUSCLES OF ORGANIC LIFE. 



271 

actual weight lifted, as far as the muscle is concerned, is equal to 
180 pounds. 

— But this is not all. The insertion of the muscle at an angle of 
10 instead of 90 degrees, takes off the purchase in the proportion, 
as mathematicians have calculated, which 173 bears to 1000. 
The augmented weight, or what is the same thing, the increase 
of power necessary to raise it, amounts, therefore, to no less than 
1058, instead of the original 60 pounds. There is yet another 
source of loss of effect in its contraction, which requires great 
additional power in the muscle to counteract it. The tendon of 
the muscle is never directly continuous with the muscular fibres, 
and the loss of power is exactly in proportion to the obliquity of 
their junction. The manner of this loss is evinced, when we 
attempt to draw a body to us, at one time with a crooked, and 
at another, with a straight bar or stick. From this cause there 
would be a further loss of power of 228 pounds, which would 
augment the muscular energy, required to raise the 60 pounds, 
up to 1284, according to this physiologist. 

— In the muscles of organic life, destined to act without the aid 
of the will, the system of antagonism, is much less perfectly de- 
veloped. These muscles are hollow, and their fibres are arranged 
generally into layers, which cross each other at right angles, 
and contribute, to a certain extent, to produce this effect. The 
alternate contractions of the auricles and ventricles of the heart, 
and of the uterus, though these organs have, properly speaking, 
no antagonist muscles, belong to this class. In some of the hollow 
organs, as the bladder, the contracted muscular fibres are ex- 
panded or antagonised, only by the matters which collect in their 
cavities. 

— The muscles of organic life, with the exception of the heart, 
are of a pale or grayish white colour. Some of them are so 
thin, and of so pale a colour, that it is impossible to draw the line 
of distinction between them and cellular or aponeurotic tissue. 
— There is a regular gradation between muscular and desmoid 
cellular tissue, and an occasional substitution of the one for the 
other, in parts that require elastic resistance, or firm support, 
that has been overlooked by anatomists. The yellow elastic 



272 CHEMICAL COMPOSITION. 

ligamentous tissue, appears to be the medium between the mus- 
cular and ligamentous tissue. Comparative anatomy shows us 
that parts formed in one animal of the elastic yellow tissue, are 
in others composed of muscular fibres. Thus, the suspensory 
ligaments of the sheath of the penis, are ligamentous in the 
horse, and muscular in the mule and bull. The middle coat of 
the arteries, which is composed of the elastic yellow tissue in 
man, is muscular in certain parts of the arterial system of the 
elephant. 

— The parietes of the urethra, which, in man, is strongly elastic, 
in the horse and many other animals is endowed with a strong 
coat of palish muscular fibres. The kindred nature of these 
two tissues, is likewise strongly manifested by chemical analysis. 
The yellow elastic tissue consists chemically of albumen, os- 
mazome and fibrine.* The thick yellow elastic ligament which 
supports the weight of the abdominal viscera in the horse, and 
others of the solipedise, consists, in man, only of the fascia su- 
perficialis abdominis, and forms, as a late writer is disposed to 
think, the abdominal pouch, (poche musculaire,) of the didelphic 
animals, such as the opossum and kangaroo. The muscular fibres 
on the inner face of the prostate glands, and the muscles of 
Wilson, on the membranous part of the urethrae seem to be 
allied to this class of tissue. It also seems borne out by the de- 
velopement of the muscles in the foetus, as previously quoted 
from Isenflam. 

— Muscles are composed chemically, according to Berzelius, prin- 
cipally of fibrine ; but they contain also albumen, gelatine, os- 
mazome, phosphates of soda, ammonia and lime, carbonate of 
lime, and some free lactic acid. If the analysis is pushed farther 
to the destruction of the flesh, there is developed a great quan- 
tity of nitrogen, hydrogen, oxygen and carbon, some iron, phos- 
phorus, soda and lime. 

* Consid. sur les aponeuroses abdom. servant d'introduction a l'histoire dcs 
Hernies, dans les Monodactyles, par Girard, fits. 



INDIVIDUAL MUSCLES. 273 



CHAPTER VIII. 

OF THE INDIVIDUAL MUSCLES. 
Muscles of the Teguments of the Cranium. 

The skin that covers the cranium is moved by a single broad 
digastric muscle, and one small pair. 

1 . Occipito-Fron talis, 

Arises fleshy from the transverse protuberant ridge near the 
middle of the os occipitis laterally, where it joins with the tem- 
poral bone ; and tendinous from the rest of that ridge back- 
wards, opposite to the lateral sinus ; it rises after the same man- 
ner on the other side. From thence it comes straight forwards, 
by a broad thin tendon, which covers the upper part of the cra- 
nium at each side, as low down as the atlollens auris, to which 
it is connected, as also to the zygoma, and covers a part of the 
aponeurosis of the temporal muscle; at the upper part of the 
forehead it becomes fleshy, and descends with straight fibres. 

Inserted into the orbicularis palpebrarum of each side, and into 
the skin of the eyebrows, sending down a fleshy slip between 
them, as far as the compressor naris and levator labii superioris 
alaeque nasi. 

Use. Pulls the skin of the head backwards ; raises the eye- 
brows upwards; and, at the same time, it draws up and wrin- 
kles the skin of the forehead. 

2. Corrugator Supercilii. 

Arises fleshy from the internal angular process of the os fron- 
tis, obove the joining of the os nasi, and nasal process of the su- 
perior maxillary bone ; from thence it runs outwards, and a little 
upwards. 

Inserted into the inner and inferior fleshy part of the occipito- 
frontalis muscle, where it joins with the orbicularis palpebrarum, 



274 



MUSCLES OF THE EAR. 



and extends outwards as far as the middle of the superciliary 
ridge. 

Use. To draw the eyebrow of that side towards the other, 
and make it project over the inner canthus of the eye. When 
both act, they pull down the skin of the forehead, and make it 
wrinkle particularly between the eyebrows. 

Muscles of the Ear. 
1. Athllens Auris, 
Arises, thin, broad, and tendinous, from the tendon of the 



Fig. 16.* 



occipito-frontalis, from 
which it is almost in- 
separable, where it co- 
vers the aponeurosis of 
the temporal muscle. 

Inserted into the up- 
per part of the ear, op- 
posite to the antihelix. 

Use. To draw the 
ear upwards, and make 
the parts, into which it 
is inserted, tense. 



2. Anterior Auris, 

Arises, thin and mem- 
branous, near the pos- 
terior part of the zygo- 
ma. 

Inserted into a small 
eminence on the back of 
the helix, opposite to the 
concha. 

Use. To draw this eminence a little forwards and upwards. 

* Fig. 16. — g, Occipito-frontalis. m, Nasal slip of do. n. Compressor naris. 
k, Levator labii superioris alaeque nasi. 5, Masseter. q, Atlollens auris. r, Re- 
trahentcs auris, usually two in number, p, Platysma myoides. 8, Stcrno-cleido- 
mastoid. u, Trapezius, v, Splenius capitis. I, Splenius colli, w, Deltoid. The 
rest of the muscles known by references to the cuts No. 17, 18, 19. 




MUSCLES OF THE EYELIDS. 



275 



3. Retrahentes Auris, 

Arise, sometimes by three, but always by two distinct small 
muscles, from the external and posterior part of the root of the 
mastoid process, immediately above the insertion of the sterno- 
cleido-mastoid muscle. 

Inserted into that part of the back of the ear which is opposite 
to the septum that divides the scapha and concha. 

Use. To draw the ear back, and stretch the concha. 

Muscles of the Eyelids. 

The palpebrae or eyelids, have one muscle common to both, 
and the upper eyelid one proper to itself. 

1. Orbicularis Palpebrarum, 

Arises, by a number of fleshy fibres, from the outer edge of 
the orbitar process of the superior maxillary bone, and from a 
tendon near the inner angle of the eye ; these run a little down- 
wards, then outwards, over the upper part of the cheek, below 
the orbit, covering the under eyelid, and surround the external 
angle, being loosely connected only to the skin and fat; run 
over the superciliary ridge of the os frontis, towards the inner 
canthus, where they intermix with those of the occipito-frontalis 
and corrugator supercilii; then covering the upper eyelid, they 
descend to the inner angle opposite to the inferior origin of this 
muscle, firmly adhering to the internal angular process of the 
os frontis, and to the short round tendon which serves to fix the 
palpebral and muscular fibres arising from it. 

Inserted, by the short round tendon, into the nasal process of 
the superior maxillary bone, covering the anterior and upper part 
of the lachrymal sac; which tendon can be easily felt at the 
inner canthus of the eye. 

Use. To shut the eye, by drawing both lids close together, the 
fibres contracting from the outer angle towards the inner, press 
the eyeball, squeeze the lachrymal gland, and convey the tears 
towards the puncta lachrymalia. 

— When the muscle is in strong action, its upper fibres cause 



276 MUSCLES OF THE EYEBALL. 

the skin of the forehead to descend, the lower ones elevate the 
integuments of the cheek. Like the other sphincters, this is a 
mixed muscle. The fibres which are supposed to be the proper 
voluntary portion, are those which correspond to the margin of 
the orbit, and are of a red colour. The involuntary fibres, form 
the thin portion which covers the lids, (musculus ciliaris ofAlbi- 
nus,) and are of a pale colour, like the muscles of organic life. 
They contract involuntarily while we are awake, in the action 
of winking, and during sleep in maintaining the lids closed. — 

The ciliaris of some authors is only a part of this muscle co- 
vering the cartilages of the eyelids, called cilia or tarsi. 

There is often a small fleshy slip, which runs down from the 
outer and inferior part of this muscle above the zygomaticus mi- 
nor, and joints with the levator labii superioris alaeque nasi. 

2. Levator Palpebrce Superioris, 

Arises from the upper part of the foramen opticum of the 
sphenoid bone, through which the optic nerve passes, above the 
levator oculi, near the trochlearis muscle. 

Inserted, by a broad thin tendon, into the cartilage that sup- 
ports the upper eyelid, named tarsus. 

Use. To open the eye, by drawing the eyelid upwards; which 
it does completely, by being fixed to the tarsus, pulling it below 
the eyebrow, and within the orbit.* 

Muscles of the Eyeball. 

The muscles which move the globe of the eye are six, viz.: 
four straight, and two oblique. 

The four straight muscles very much resemble each other: all 
Arising by a narrow beginning, a little tendinous and fleshy, 
from the bottom of the orbit around the foramen opticum of the 
sphenoid bone, where the optic nerve enters, so that they may 
be taken out adhering to this nerve; and all having strong fleshy 
bellies. 

* There is no antagonist muscle provided especially to depress the lower lid. 
Its depression is effected, according to the suggestion of Sir C.Bell, by the protru- 
sion of the eyeball.— p. 



MUSCLES OF THE EYE. 977 

Inserted at the forepart of the globe of the eye into the anterior 
part of the tunica sclerotica, and under the tunica adnata, at op- 
posite sides, which indicates both their names and Use ; so that 
they scarcely require any farther description than to name them 

singly. 

1. Levator Oculi, (Rectus Superior,) 

Arises from the upper part of the foramen opticum of the sphe- 
noid bone, below the levator palpebral superioris, and runs for- 
wards to be 

Inserted into the superior and forepart of the tunica sclerotica, 
by a broad thin tendon. 

Use. To raise up the globe of the eye. 

2. Depressor Oculi, (Rectus Inferior,) 

Arises from the inferior part of the foramen opticum. 

Inserted opposite to the former. 

Use. To pull the globe of the eye down. 

3. Adductor Oculi, (Rectus Internus,) 

Arises, as the former, between the obliquus superior and de- 
pressor, being, from its situation, the shortest. 
Inserted opposite to the inner angle. 
Use. To turn the eye towards the nose. 

4. Adductor Oculi, (Rectus Externus,) 

Arises from the bony partition between the foramen opticum 
and lacerum, being the longest from its situation ; and is 
Inserted into the globe opposite to the outer canthus. 
Use. To move the globe outwards. 
The oblique muscles are two: 

Obliquus Superior, seu Trochlearis, 
Arises, like the straight muscles, from the edge of the foramen 
opticum at the bottom of the orbit, between the levator and ad- 
ductor oculi ; from thence, runs straight along the pars plana of 
the ethmoid bone to the upper part of the orbit, where a cartila- 
vol. i. 24 



278 MUSCLE OF THE NOSE. 

ginous trochlea is fixed to the inside of the internal angular pro- 
cess of the os frontis, through which its tendon passes, and runs 
a little downwards and outwards, enclosed in a loose membra- 
nous sheath. 

Inserted, by a broad thin tendon, into the tunica sclerotica, 
about half way between the insertion of the atlollens oculi and 
optic nerve. 

Use. To roll the globe of the eye, and turn the pupil down- 
wards and outwards, so that the upper side of the globe is turned 
inwards, and the inferior part to the outside of the orbit, and the 
whole globe drawn forwards towards their inner canthus. 

2. Obliquus Inferior, 

Arises, by a narrow beginning, from the outer edge of the 
orbitar process of the superior maxillary bone, near its juncture 
with the os unguis ; and running obliquely outwards, is 

Inserted into the sclerotica, in the space between the adductor 
and optic nerve, by a broad and thin tendon. 

Use. To draw the globe of the eye forwards, inwards, and 
downwards; and, contrary to the superior, to turn the pupil up- 
wards towards the inner extremity of the eyebrow ; at the same 
time, the external part of the globe is turned towards the inferior 
side, and the internal rolls towards the upper part. 

The Muscle of the Nose. 

There is only one muscle on each side that can be called 
proper to the nose, though it is affected by several muscles of 
the face. 

Compressor JVaris, (Triangularis seu Transversalis Nasi,) 

Arises, by a narrow beginning, from the root of the ala nasi 
externally, where part of the levator labii superioris alaeque nasi 
is connected to it ; it spreads into a number of thin separate 
fibres, which run up along the cartilage in an oblique manner 
towards the dorsum of the nose, where it joins with its fellow, 
and is 

Inserted slightly into the anterior extremity of the os nasi and 



MUSCLES OF THE MOUTH AND UPS. 



279 



nasal process of the superior maxillary bone, where it meets 
with some of the fibres descending from the occipito-frontalis 
muscle.* 

Use. To compress the ala towards the septum nasi, particu- 
larly when we want to smell acutely ; but, if the fibres of the 
frontal muscle, which adhere to it, act, the upper part of this thin 
muscle assists to pull the ala outwards. It also corrugates the 
skin of the nose, and assists in expressing certain passions. — It 
has been called by Columbus dilataus nasi, from a belief, in which 
Bougery coincides, that when it acts with its extremity upon the 
nose as the fixed point, it dilates the nostril. When the other 
extremity of the muscle is the fixed point, it compresses it. — 



Fig. 17. 



Muscles of the Mouth and 
Lips. 

The mouth has nine 
pair of muscles, which are 
inserted into the lips, and 
a common one formed by 
the termination of these, 
viz. three above, three 
below, three outwards, and 
the common muscle sur- 
rounds the mouth. 

The three above are, 

1. Levator Anguli Oris, 

Arises, thin and fleshy, 
from the hollow of the 
superior maxillary bone, 
between the root of the 
socket of the first dens molaris and the foramen infra orbita- 
rium. 

* The nasal slip of fibres descending from the occipito-frontalis, is sometimes 
spoken of as a distinct muscle, under the name of Pyramid Mis nasi. Fig. 17. — g, 
Occipito-frontalis. I, Levator labii superioris ala?que nasi. Z, Levator anguli oris. 
72, Compressor naris. o, Orbicularis palpebrarum ; the external palpebral ligament, 




2Q0 MUSCLES OF THE FACE. 

Inserted into the angle of the mouth and under lip, where it 
joins with its antagonist. 

Use. To draw the corner of the mouth upwards, and make 
that part of the cheek opposite to the chin prominent, as in 
smiling. 

2. Levator Labii Superioris Alceque Nasi, 

Arises by two distinct origins: the first broad and fleshy, from 
the external part of the orbitar process of the superior maxillary 
bone which forms the lower part of the orbit, immediately above 
the foramen infra-orbitarium ; the second portion arises from the 
nasal process of the superior maxillary bone, where it joins the 
os frontis at the inner canthus, descending along the edge of the 
groove for the lachrymal sac. 

The first and shortest portion is 

Inserted into the upper lip and orbicularis labiorum ; the 
second and longest, into the upper lip and outer part of the ala 
nasi. 

Use. To raise the upper lip towards the orbit, and a little out- 
wards ; the second portion serves to draw the skin of the nose 
upwards and outwards, by which the nostril is dilated. 

3. Depressor Labii Superioris Alceque Nasi, 

Arises, thin and fleshy, from the os maxillare superius, imme- 
diately above the joining of the gums with the two dentes inci- 
sores and the dens caninus ; from thence it runs up under part of 
the levator labii superioris alasque nasi. 

Inserted into the upper lip and root of the ala nasi. 

Use. To draw the upper lip and ala nasi downwards and 
backwards. 

The three below are, 



seen on the right side, extending to the ear. 3 3, Zygomaticus major, and minor. 
4, Orbicularis oris, with the slip to the lower part of the septum of the nose, called 
by Albinus, nasalis labii superioris. 5, Masseter. t, Depressor anguli oris, s s, 
Sternal and clavicular portions of the sterno-cleido-mastoid. w, Trapezius seen at 
its upper part. 6, Sterno-hyoid. 7, Slcrno-thyroid. 8, Omo-hyoid. 9, Scalenus 
anticus. 10, Scalenus medius. 



MUSCLES OF THE FACE. 



281 



1. Depressor Anguli Oris, 

Arises, broad and fleshy, from the lower edge of the maxilla 
inferior, at the side of the chin, being firmly connected to that 
part of the platysma myoides, which runs over the maxilla to 
the angle of the mouth, to the depressor labii inferioris within, 
and to the skin and fat without, gradually turning narrower : 
and is 

Inserted into the angle of the mouth, joining with the zygo- 
matics major and levator anguli oris. 

Use. To pull down the corner of the mouth. 

2. Depressor Labii Inferioris, 

Arises, broad and fleshy, intermixed with fat, from the inferior 
part of the lower jaw next to the chin; runs obliquely upwards, 
and is 

Inserted into the edge of the under lip, extends along one half 
of the lid, and is lost in its red part. 

Use. To pull the under lip and the skin of the side of the 
chin downwards, and a little outwards. 



3. Levator Labii Inferioris, 

Arises, from the lower jaw, at 
the roots of the alveoli of two 
dentes incisores and of the cani- 
nus; is 

Inserted into the under lip and 
skin of the chin, 

Use. To pull the parts, into 
which it is inserted, upwards. 

The three outward are, 

1. Buccinator, 

Arises, tendinous and fleshy, 
from the lower jaw, as far back 



Fig. 18.* 




* Fig. 18. — a, Depressor labii inferioris. b, Buccinator, c, Levator anguli 
oris, e, Levator labii inferioris (levator menti ;) this will be best seen in dissection 

24* 



282 MUSCLES OF THE FACE. 

as the last dens molaris and forepart of the root of the coronoid 
process ; fleshy from the upper jaw, between the last dens mo- 
laris and pterygoid process of the sphenoid bone ; from the ex- 
tremity of this process it arises tendinous, being continued between 
both jaws to the constrictor pharyngis superior, with which it 
joins ; from thence, proceeding with straight fibres, and adhering 
close to the membrane that lines the mouth, it is 

Inserted into the angle of the mouth within the orbicularis 
oris. 

Use. To draw the angle of the mouth backwards and out- 
wards, and contract its cavity, by pressing the cheek inwards, 
by which the food is thrust between the teeth. — The buccinator 
acts principally in front on the commissure of the lips, which it 
draws backwards horizontally, increasing the transverse aper- 
ture of the mouth, and throwing the cheek into the vertical folds, 
so conspicuous in old age. It thus antagonises the orbicularis 
oris. If both these muscles act together, the lips are extended 
and pressed against the teeth. When the cavity of the mouth 
is distended with air or liquids, the fibres of this muscle are pro- 
truded and curved. If the muscle now acts, the fibres become 
straightened, and the fluid is expelled from the mouth, suddenly 
or gradually, according to the resistance made by the orbicu- 
laris. 

— This muscle assists also in mastication and deglutition, by 
pressing the food from between the cheek and gums into the 
cavity of the mouth. — 

2. Zygomaticus Major, 

Arises, fleshy, from the os malae, near the zygomatic suture. 

Inserted into the angle of the mouth, appearing to be lost in 
the depressor anguli oris and orbicularis oris. 

Use. To draw the corner of the mouth and under lip towards 
the origin of the muscle, and make the cheek prominent, as in 
laughing. 

by inverting the lip and dissecting off the mucous membrane. /, Depressor anguli 
oris. 5, Masseter. g, Tendon of the superior or internal oblique muscle of the 
eye, after it passes its trochlea, h, Inferior oblique. 



MUSCLES OF THE LOWER JAW 



283 



2. Zygomaiicus Minor, 

Arises from the upper prominent part of the os malae, above 
the origin of the former muscle; and, descending obliquely 
downwards and forwards, is 

Inserted into the upper lip, near the corner of the mouth, along 
with the levator anguli oris. 

Use. To draw the corner of the mouth obliquely outwards 
and upwards towards the external canthus of the eye. 

The common muscle is the 

Orbicularis Oris. 

This muscle is, in a great measure, formed by the muscles 
that move the lips ; the fibres of the superior descending, those 
of the inferior ascending, and decussating each other about the 
corner of the mouth, run along the lip to join those of the oppo- 
site side, so that the fleshy fibres appear to surround the mouth 
like a sphincler. 

Use. To shut the mouth, by contracting and drawing both lips 
together, and to counteract all the muscles that assist in form- 
ing it. 

There is another small muscle described by Albinus, which he 
calls JVasalis labii superioris; but it seems to be only some fibres 
of the former connected to the septum nasi. 

— The orbicularis, possesses a very varied and extensive ac- 
tion, and may act as a whole or in parts. Its simplest action is 
to close the mouth by bringing the lips together. The upper or 
lower labial fibres may act separately, as well as those at the 
commissures of the lips, by which they are enabled in turn, to 
antagonise the different muscles which are attached around. By 
a very strong contraction of the labial and commissural fibres, 
the lips are thrown forwards in a circular projection, as in 
whistling. By the contraction of the inner labial fibres, they are 
drawn inwards upon the teeth. — 

Muscles of the Lower Jaw. 
The lower jaw has four pair of muscles for its elevation or 



284 MUSCLES OF THE LOWER JAW. 

lateral motions, namely, two, which are seen on the side of the 
face, and two concealed by the angle of the jaw. 

1. Temporalis, 

Arises, fleshy, from a semicircular ridge of the lower and late- 
ral part of the parietal bone, from all the pars squamosa of the 
temporal bone, from the external angular process of the os fron- 
tis, from the temporal process of the sphenoid bone, and from an 
aponeurosis which covers it ; from these different origins the 
fibres descend like radii towards the jugum, under which they 
pass; and are 

Inserted, by a strong tendon, into the upper part of the coro- 
noid process of the lower jaw ; in the duplicature of which ten- 
don this process is enclosed as in a sheath, being continued down 
all its forepart to near the last dens molaris. 

Use. To pull the lower jaw upwards, and press it against the 
upper, at the same time drawing it a little backwards. 

JV*. B. This muscle is covered with a tendinous membrane, 
called its aponeurosis, which arises from the bones that give ori- 
gin to the upper and semicircular part of the tnuscle ; and de- 
scending over it, is inserted into all the jugum, and the adjoining 
part of the os frontis. 

The use of this membrane is to give room for the origin of a 
greater number of fleshy fibres, to fortify the muscle in its ac- 
tion, and to serve as a defence to it. 

2. Masseter, 

Arises, by strong, tendinous, and fleshy fibres, which run in 
different directions, from the superior maxillary bone, where it 
joins the os malae, and from the inferior and anterior part of the 
zygoma, its whole length, the external fibres slanting backwards, 
and the internal forwards. 

Inserted into the angle of the lower jaw, and from that up- 
wards to near the top of its coronoid process. 

Use. To pull the lower to the upper jaw, and by means of its 
oblique decussation, a little forwards and backwards. 



MUSCLES OF THE NECK. 



285 



3. Pteryguideus Internus, 

Arises, tendinous and fleshy, from the inner and upper part of 
the internal plate of the ptery- 



Fig. 19.* 




goid process, filling all the space 
between the two plates ; and 
from the pterygoid process of 
the os palati between these 
plates. 

Inserted into the angle of the 
lower jaw internally. 

Use. To draw the jaw up- 
wards, and obliquely towards 
the opposite side. 



4. Pterygoideus Externus, 

Arises from the outer side of 
the external plate of the ptery- 
goid process of the sphenoid bone, from part of the tuberosity of 
the os maxillare adjoining to it, and from the root of the tempo- 
ral process of the sphenoid bone. 

Inserted into the cavity in the neck of the condyloid process 
of the lower jaw ; some of its fibres are inserted into the liga- 
ment that connects the movable cartilage and that process to 
each other. 

Use. To pull the lower jaw forwards, and to the opposite side ; 
and to pull the ligament from the joint, that it may not be pinch- 
ed during these motions : when both external pterygoid muscles 
act, the fore teeth of the under jaw are pushed forwards beyond 
those of the upper jaw. 

The Muscles which appear about the anterior part of the Neck. 
On the side of the neck are two muscles, or layers. 

1. Musculus Cutaneus, vulgo Platysma Myoides, (see Fig. 16,) 
Arises, by a number of slender separate fleshy fibres, from the 

*Fig. 19. — b, Buccinator, d, Depressor labii inferioris. h, Corrugator Super- 
cilii. n, Compressor naris. s, Stcrno-cleido-maptoid. t, Temporal, u, Tra- 
pezius, v, Splcnius capitis, v, Splcnius colli, x, Digastricus. y, Mylo-hyoid. 
s, Stylo liyoid. &, Hyo-glossus. 



286 MUSCLES OF THE NECK. 

cellular substance that covers the upper parts of the deltoid and 
pectoral muscles; in their ascent they all unite to form a thin 
muscle, which runs obliquely upwards along the side of the neck, 
adhering to the skin. 

Inserted into the lower jaw, between its angle and the origin 
of the depressor anguli oris, to which it is firmly connected, and 
but slightly to the skin that covers the inferior part of the mas- 
seter muscle and parotid glands. 

Use. To assist the depressor anguli oris in drawing the skin of 
the cheek downwards ; and when the mouth is shut, it draws all 
that part of the skin, to which it is connected, below the lower 
jaw, upwards. — Some of its fibres are inserted into the angle of 
the mouth, and are connected with the muscles of that region. 
They draw the corner of the mouth downwards, and constitute 
the musculus risorius of Santorini. — 

2. Stemo-cleido-mastoideus, {see Fig. 17,) 

Arises by two distinct origins : the anterior tendinous and a 
little fleshy, from the top of the sternum near its junction with the 
clavicle ; the posterior, fleshy, from the upper and anterior part 
of the clavicle; both unite a little above the anterior articulation 
of the clavicle, to form one muscle, which runs obliquely up- 
wards and outwards, to be 

Inserted, by a thick strong tendon, into the mastoid process, 
which it surrounds ; and, gradually turning thinner, is inserted 
as far back as the lambdoid suture. 

Use. To turn the head to one side, and bend it forwards. 

Muscles situated betiveen the Lower Jaw and Os Hyoides. 

There are four layers before, and two muscles at the side. 
The four layers are, 

1. Digastricus, {see Fig. 18,) 

Arises, by a fleshy belly, intermixed with tendinous fibres, 
from the fossa at the root of the mastoid process of the temporal 
bone, and soon becomes tendinous; runs downwards and for- 
wards : the tendon passes generally through the stylo-hyoideus 



MUSCLES OF THE NECK. 287 

muscle ; then it is fixed by a ligament to the os hyoides ; and, 
havino- received from that bone an addition of tendinous and 
muscular fibres, runs obliquely forwards, turns fleshy again, 

and is 

Inserted, by its anterior belly, into a rough sinuosity at the in- 
ferior and anterior edge of that part of the lower jaw called the 

chin. 

Use. To open the mouth by pulling the lower jaw downwards, 
and backwards ; and when the jaws are shut, to raise the os 
hyoides, and, consequently, the pharynx, upwards, as in deglu- 
tition. 

2. Mylo-Hyoideus, (See Fig. 18,) 

Arises, fleshy, from all the inside of the lower jaw, between 
the last dens molaris and the middle of the chin, where it joins 
with its fellow. 

Inserted into the lower edge of the basis of the os hyoides, 
and joins with its fellow. 

Use. To pull the os hyoides forwards, upwards, and to one side. 

3. Genio-Hyoidens, 

Arises, tendinous, from a rough protuberance in the middle of 
the lower jaw internally, or on the inside of the chin. 
Inserted into the basis of the os hyoides. 
Use. To draw this bone forwards to the chin. 

4. Genio-Hrjo-Glossus. 

Arises, tendinous, from a rough protuberance in the inside of 
the middle of the lower jaw ; its fibres run like a fan, forwards, 
upwards, and backwards ; and are 

Inserted into the whole length of the tongue, and base of the 
os hyoides, near its cornu. 

Use. According to the direction of its fibres, to draw the tip 
of the tongue backwards into the mouth, the middle downwards, 
and to render its dorsum concave ; to draw its root and os hy- 
oides forwards, and to thrust the tongue out of the mouth. 

The two muscles at the side are, 



;2gg MUSCLES OF THE NECK. 

1. Hyo-Glossus, 

Arises, broad and fleshy, from the base, cornu, and appendix 
of the os hyoides ; the fibres run upwards and outwards ; to be 
Inserted into the side of the tongue, near the stylo-glossus. 
Use. To pull the tongue inwards and downwards. 

2. Lingualis, 

Arises from the root of the tongue laterally ; runs forwards 
between the hyo-glossus and genio-glossus, to be 

Inserted into the tip of the tongue, along with part of the sty- 
lo-glossus. 

Use. To contract the substance of the tongue, and bring it 
backwards, and to elevate the point of the tongue. 

Muscles situated between the Os Hyoides and Trunk. 

These may be divided into two layers. 
The first layer consists of two muscles, 

1. Sterno-Hyoideus, 

Arises, thin and fleshy, from the cartilaginous extremity of the 
first rib, the upper and inner part of the sternum, and from the 
clavicle where it joins with the sternum. 

Inserted into the base of the os hyoides. 

Use. To pull the os hyoides downwards. 

2. Omo-Hyoideus, 

Arises, broad, thin, and fleshy, from the superior costa of the 
scapula, near the semilunar notch, and from the ligament that 
runs across it ; thence ascending obliquely, it becomes tendinous 
below the sterno-cleido-mastoid muscle; and, growing fleshy 
again, is 

Inserted into the base of the os hyoides, between its cornu and 
the insertion of the sterno-hyoideus. 

Use. To pull the os hyoides obliquely downwards. 

The second layer consists of three muscles. 



MUSCLES BETWEEN THE JAW AND OS HYOIDES. 289 

1 . Sterno- Tkyroideus, 

Arises, fleshy, from the whole edge of the uppermost bone of 
the sternum internally, opposite to the cartilage of the first rib, 
from which it receives a small part of its origin. 

Inserted into the surface of the rough line at the external part 
of the inferior edge of the thyroid cartilage. 

Use. To draw the larynx downwards. 

2. Thyro-Hyoideus, 

Arises from the rough line opposite to the former. 

Inserted into part of the basis, and almost all the cornu of the 
os hyoides. 

Use, To pull the os hyoides downwards, or the thyroid car- 
tilage upwards. 

3. Crico-Thyroideus, 

Arises from the side and forepart of the cricoid cartilage, 
running obliquely upwards. 

Inserted by two portions ; the first, into the lower part of the 
thyroid cartilage ; the second, into its inferior cornu. 

Use. To pull forwards and depress the thyroid, or to elevate 
and draw backwards the cricoid cartilage. 

Muscles situated between the Lower Jaw and Os Hyoides 

laterally. 
They are five in number. They proceed from the styloid 
process of the temporal bone, from which they have half of 
their names ; and two from the pterygoid process of the sphe- 
noid bone. 

The three from the styloid process are, 

1. Stylo- Glossus, 

Arises, tendinous and fleshy, from the styloid process, and 
from a ligament that connects that process to the angle of the 
lower jaw. 

vol. i. 25 



290 STYLOID MUSCLES. 

Inserted into the root of the tongue, runs along its side, and is 
insensibly lost near its apex. 

Use. To draw the tongue laterally and backwards. 

2. Stylo-Hyoideus, 

Arises, by a round tendon, from the middle and inferior part 
of the styloid process. 

Inserted into the os hyoides at the junction of the base and 
cornu. 

Use. To pull the os hyoides to one side, and a little upwards. 

JV. B. Its fleshy belly is generally perforated by the tendon of 
the digastric muscle, on one or both sides. There is often an- 
other accompanying it, called stylo-hyoideus alter ; and has the 
same origin, insertion, and use. 

3. Stylo- Pharyngeus, 

Arises, fleshy, from the root of the styloid process. 

Inserted into the side of the pharynx and back part of the 
thyroid cartilage. 

Use. To dilate and raise the pharynx and thyroid cartilage 
upwards. 

The two from the pterygoid process are, 

1. Circumflexus, or Tensor Palati, 

Arises from the spinous process of the sphenoid bone, behind 
the foramen ovale, which transmits the third branch of the fifth 
pair of nerves, from the Eustachian tube, not far from its osse- 
ous part ; it then runs down along the pterygoideus internus, 
passes over the hook of the internal plate of the pterygoid pro- 
cess by a round tendon, which soon spreads into a broad mem- 
brane. 

Inserted into the velum pendulum palati, and the semilunar 
edge of the os palati, and extends as far as the suture which 
ioins the two bones. Generally some of its posterior fibres join 
with the constrictor pharyngis superior, and palato-pharyngeus. 

Use. To stretch the velum, to draw it downwards, and to one 



MUSCLES OF THE PALATE. 291 

side towards the hook. It has little effect upon the tube, being 
chief!)' connected to its osseous part. 

2. Levator Palati, 

Arises, tendinous and fleshy, from the extremity of the pars 
petrosa of the temporal bone, where it is perforated by the Eusta- 
chian tube, and also from the membranous part of the same tube. 

Inserted into the whole length of the velum pendulum palati, 
as far as the root of the uvula, and unites with its fellow. 

Use. To draw the velum upwards and backwards, so as to 
shut the passage from the fauces into the mouth and nose. 

Muscles situated about the passage of the Fauces. 

There are two on each side, and a single one in the middle. 
The two on each side are, 

1. Constrictor Isthmi Faucium, 

Arises, by a slender beginning, from the side of the tongue, 
near its root; thence running upwards within the anterior arch, 
before the amygdala, it is 

Inserted into the middle of the velum pendulum palati, at the 
root of the uvula anteriorly, being connected with its fellow, and 
with the beginning of the palato-pharyngeus. 

Use. Draws the velum towards the root of the tongue, which 
it raises at the same time, and with its fellow, contracts the pas- 
sage between the two arches, by which it shuts the opening into 
the fauces. 

2. Palato-Pharyngeus, 

Arises, by a broad beginning, from the middle of the velum 
palati, at the root of the uvula posteriorly, and from the tendinous 
expansion of the circumflexus palati. The fibres are collected 
within the posterior arch behind the amygdala, and run back- 
wards to the top and lateral part of the pharynx, where the 
fibres are scattered, and mix with those of the stylo-pharyngeus. 

Inserted into the edge of the upper and back part of the thy- 



292 MUSCLES OF THE FAUCES. 

roid cartilage ; some of the fibres being lost between the mem- 
brane of the pharynx, and the two inferior constrictors. 

Use. Draws the uvula and velum downwards and backwards; 
and, at the same time, pulls the thyroid cartilage and pharynx 
upwards, and shortens it; with the constrictor superior and 
tongue, it assists in shutting the passage into the nostrils ; and, 
in swallowing, it thrusts the food from the fauces into the pha- 
rynx. 

Salpingo-Pharyngeus, {from gaXtfiXS;, trumpet,) 

Of Albinus, is composed of a few fibres of this muscle, which 

Arise from the anterior and lower part of the cartilaginous 
extremity of the Eustachian tube ; and are, 

Inserted into the inner part of the last-mentioned muscle. 

Use. To assist the former, and to dilate the mouth of the 
tube. 

The one in the middle is the 

Azygos Uvulce, 

Arises, fleshy, from the extremity of the suture which joins the 
palate bones, runs down the whole length of the velum and uvula, 
resembling a small earth-worm, and adhering to the tendons of 
the circumflexi. 

Inserted into the apex of the uvula. 

Use. Raises the uvula upwards and forwards, and shortens it. 

Muscles situated on the posterior part of the Pharynx. 
Of these there are three pair : 

1. Constrictor Pharyngis Inferior, 

Arises from the side of the thyroid cartilage, near the attach- 
ment of the thyroideus and thyro-hyoideus muscles; and from 
the cricoid cartilage, near the crico-thyroideus. This muscle is 
the largest of the three ; and is 

Inserted into the white line, where it joins with its fellow; the 
superior fibres running obliquely upwards, covering nearly one 
half of the middle constrictor, and terminating in a point ; the 



MUSCLES OF THE GLOTTIS. 293 

inferior fibres run more transversely and covers the beginning 
of the oesophagus. 

Use. To compress that part of the pharynx which it covers, 
and to raise it with the larynx a little upwards. 

2. Constrictor Pharyngis Medius, 

Arises from the appendix of the os hyoides, from the cornu of 
that bone, and from the ligament which connects it to the thyroid 
cartilage; the fibres of the superior part running obliquely up- 
wards, and, covering a considerable part of the superior con- 
strictor, terminate in a point. 

Inserted into the middle of the cuneiforme process of the os 
occipitis, before the foramen magnum, and joined to its fellow at 
a white line in the middle back part of the pharynx. The fibres 
at the middle part run more transversely than those above or 
below. 

Use. To compress that part of the pharynx which it covers, 
and to draw it and the os hyoides upwards. 

3. Constrictor Pharyngis Superior, 

Arises, above, from the cuneiforme process of the os occipitis, 
before the foramen magnum, near the holes where the ninth pair 
of the nerves passes out ; lower down, from the pterygoid pro- 
cess of the sphenoid bone ; from the upper and under jaw, near 
the roots of the last dentes molares; and between the jaws, it is 
continued with the buccinator muscle; and with some fibres 
from the root of the tongue, and from the palate. 

Inserted into a white line in the middle of the pharynx, where 
it joins with its fellow, and is covered by the constrictor medius. 

Use. To compress the upper part of the pharynx, and draw 
it forwards and upwards, 

Muscles situated about the Glottis. 

They consist generally of four pair of small muscles, and a 
single one. 

•25 * 



294 MUSCLES OF THE GLOTTIS. 

1. Crico-Arytcenoideus Posticus, 

Arises, fleshy, from the back part of the cricoid cartilage ; 
and is 

Inserted into the posterior part of the base of the arytenoid 
cartilage. 

Use. To open the rima glottidis a little, and, by pulling back 
the arytenoid cartilage, to stretch the ligament so as to make it 
tense. 

2. Crico-Arytcenoideus Lateralis, 

Arises, fleshy, from the cricoid cartilage, laterally, where it is 
covered by part of the thyroid, and is 

Inserted into the side of the base of the arytenoid cartilage 
near the former. 

Use. To open the rima glottidis, by pulling the ligaments from 
each other. 

3. Thyreo-Arytanoideus, 

Arises from the under and back part of the middle of the thy- 
roid cartilage; and, running backwards and a little upwards, 
along the side of the glottis, is 

Inserted into the arytenoid cartilage, higher up and farther 
forwards than the crico-arytaenoideus lateralis. 

Use. To pull the arytenoid cartilage forwards nearer the mid- 
dle of the thyroid, and consequently to shorten and relax the 
ligament of the larynx or glottis vera. 

4. Arytamoideus Obliquus, 

Arises from the base of one arytenoid cartilage ; and, crossing 
its fellow, is 

Inserted near the tip of the other arytenoid cartilage. 

Use. When both act they pull the arytenoid cartilages to- 
wards each other. 

JV. B. One of these is very often wanting. 

The single muscle is, the 



MUSCLES OF THE GLOTTIS. . 295 

ArytcBnoideus Transversus, 

Arises from the side of one arytenoid cartilage, from near its 
articulation with the cricoid to near its tip. The fibres run 
straight across, and are 

Inserted, in the same manner, into the other arytenoid car- 
tilage. 

Use. To shut the rima glottidis, by bringing 'these two carti- 
lages, with the ligaments, nearer one another. 

Besides these, there are a few separate muscular fibres on 
each side ; which, from their general direction, are named, 

1. Thyreo-Epiglottideus, 

Arises, by a few pale separated fibres, from the thyroid car- 
tilage : and is 

Inserted into the epiglottis laterally. 

Use. To draw the epiglottis obliquely downwards, or, when 
both act, directly downwards ; and at the same time, it expands 
that soft cartilage. 

2. Arytceno-Epiglottideus, 

Arises, by a number of small fibres, from the lateral and up- 
per part of the arytenoid cartilage ; and, running along the outer 
side of the external rima, is 

Inserted into the epiglottis along with the former. 

Use. To pull that side of the epiglottis towards the external 
rima ; or, when both act, to pull it close upon the glottis. It is 
counteracted by the elasticity of the epiglottis. 

Muscles situated on the anterior Part of the Neck, close to the 
Vertebra. 

These consist of one layer, formed by four muscles. 

1. Longus Colli, 

Arises, tendinous and fleshy from the bodies of the three ver- 
tebras of the back laterally ; and from the transverse process of 



296 MUSCLES OF THE SIDE OF THE NECK 

the third, fourth, fifth, and sixth vertebras of the neck, near their 
roots. 

Inserted into the forepart of the bodies of all the vertebras of 
the neck, by as many small tendons, which are covered with 
flesh. 

Use. To bend the neck gradually forwards, and to one side. 

2. Rectus Capitis Internus Major, 

Arises from the anterior points of the transverse process of 
the third, fourth, fifth, and sixth vertebras of the neck, by four 
distinct beginnings. 

Inserted into the cuneiforme process of the os occipitis, a little 
before the condyloid process. 

Use. To bend the head forwards. 

3. Rectus Capitis Internus Minor, 

Arises, fleshy, from the forepart of the body of the first verte- 
bra of the neck opposite to the superior oblique process. 

Inserted near the root of the condyloid process of the os oc- 
cipitis, under, and a little farther outwards, than the former 
muscle. 

Use. To bend the head forwards. 

4. Rectus Capitis Lateralis, 

Arises, fleshy, from the anterior part of the point of the trans- 
verse process of the first vertebra of the neck. 

Inserted into the os occipitis, opposite to the foramen stylo- 
mastoideum of the temporal bone. 

Use. To bend the head a little to one side. 

Muscles situated on the Anterior Part of the Thorax. 

These may be divided into two layers. The first layer con- 
sists of one muscle, named 

Pectoralis Major, 

Arises from the cartilaginous extremities of the fifth and sixth 
ribs, where it always intermixes with the external oblique muscle 



MUSCLES OF THE THORAX. 297 

of the abdomen ; from almost the whole length of the sternum : 
and from near half of the anterior part of the clavicle; the 
fibres run towards the axilla in a folding manner. 

Inserted, by two broad tendons, which cross each other at the 
upper and inner part of the os humeri, above the insertion of 
the deltoid muscle, and outer side of the groove for lodging the 
tendon of the long head of the biceps. 

Use. To move the arm forwards, and obliquely upwards, to- 
wards the sternum. 

The second layer consists of three muscles. 

1. Subclavius, 

Arises, tendinous, from the cartilage that joins the first rib to 
the sternum. 

Inserted, after becoming fleshy, into the inferior part of the 
clavicle, which it occupies from within an inch of the sternum, 
as far outwards as to its connexion, by ligament, with the cora- 
coid process of the scapula. 

Use. To pull the clavicle downwards and forwards. 

2. Pectoralis Minor, 

Arises, tendinous and fleshy, from the upper edge of the third, 
fourth, and fifth ribs, near where they join with their cartilages. 

Inserted, tendinous, into the coracoid process of the scapula : 
but soon grows fleshy and broad. 

Use. To bring the scapula forwards and downwards, or to 
raise the ribs upwards. 

3. Serratus Magnus, 

Arises from the nine superior ribs, by an equal number of 
fleshy digitations, resembling the teeth of a saw. 

Inserted, fleshy, into the whole base of the scapula internally, 
between the insertion of the rhomboid and the origin of the sub- 
scapulars muscle, being folded about the two angles of the 
scapula. 

Use. To move the scapula forwards : and, when the scapula 
is forcibly raised, to draw upwards the ribs. 



298 MUSCLES OF THE THORAX. 

Muscles situated between the Ribs, and within the Thorax. 

Between the ribs, on each side, there are eleven double rows 
of muscles, which are, therefore, named intercostah. These de- 
cussate each other like the strokes of the letter X. 

1. Intercostales Exlerni, 

Arise from the inferior acute edge of each superior rib, and 
run obliquely forwards, the whole length from the spine to near 
the joining of the ribs with their cartilages ; from which, to the 
sternum, there is only a thin membrane covering the internal in- 
tercostals. 

Inserted into the upper obtuse edge of each inferior rib, as far 
back as the spine, into which the posterior portion is fixed. 

2. Intercostales Interni, 

Arise in the same manner as the external : but they begin at 

the sternum, and run obliquely backwards, as far as the angle 

of the rib ; and from that to the spine they are wanting. 

Inserted in the same manner, as the external. 

Use. By means of these muscles, the ribs are equally raised 

upwards, during inspiration. Their fibres being oblique, give 

them a greater power of bringing the ribs near each other, than 

could be performed by straight ones. But, by the obliquity of 

the fibres, they are almost brought contiguous: and as the fixed 

points of the ribs are before and behind, if the external had been 

continued forwards to the sternum, and the internal backwards 

to the spine, it would have hindered their motion, which is 

greatest in the middle, though the obliquity of the ribs renders it 

less perceptible; and, instead of raising the fibres fixed to the 

sternum and spine, woukl have depressed the ribs. 

N. B. The portions of the external intercostals, which arise 
from the transverse processes of the vertebras where the ribs are 
fixed to them, and other portions that pass over one rib and ter- 
minate in the next below it, Albinus calls Levatores costarurn lon- 
%iores et breviores. 

The portions of the internal that pass over one rib, and are 



ABDOMINAL MUSCLES. 



299 



inserted into the next below it, are, by Douglas, called Costarum 
depressores proprii Cowperi. 

These portions of both rows assist in raising the ribs in the 
same manner as the rest of the intercostals. 

The muscles within the thorax form one pair, viz. 

Triangularis, or Sterno-Costalis, 

Arises, fleshy, and a little tendinous, from all the length of the 
cartilago-ensiformis laterally, and from the edge of the lower 
half of the middle bone of the sternum, from whence its fibres 
ascend obliquely upwards and outwards. 

Inserted, generally by three triangular terminations, into the 
lower edge of the cartilages of the third, fourth, and fifth ribs ; 
near where these join with the ribs. 

Use. To depress these cartilages, and the extremities of the 
ribs ; and consequently to assist in contracting the cavity of the 
thorax. 

This muscle often varies ; and is sometimes inserted into the 
cartilage of the second rib, sometimes into the cartilages of the 
sixth rib. 

Muscles situated on the anterior part of the Abdomen. 

They consist of three broad layers on each side of the belly 
and, of one layer in front. 
The three layers are : 

1. Obliquus Descendens Externus, 

Arises, by eight heads, from the lower edges of an equal num- 
ber of inferior ribs, at a little distance from their cartilages : it 
always intermixes in a serrated manner, with portions of the 
serratus major anticus; and generally coheres to the pecto- 
ralis major, intercostals, and latissimus dorsi ; which last covers 
the edge of a portion of it extended from the last rib to the spine 
of the ilium. — It interdigitates by its five upper heads with the 
serratus major anticus, and by the three lower with the latissimus 
dorsi, where the latter arises from the ribs; a slip from the pec- 
toralis covers the first or upper head. — 



»()() ABDOMINAL MUSCLES. 

From these origins the fibres run obliquely downwards and 
forwards, and terminate in the anterior half of the spine of the 
ilium, and in a tendinous membrane, whose fibres are continued 
in the same direction until they meet the fibres of the correspond- 
ing tendon of the other side, in a line which extends from the 
ensiform cartilage to the os pubis. 

This line is called linca alba, from its white appearance, which 
is owing to the connexion of three tendons with each other, 
without the intervention of muscles, namely, those of the exter- 
nal and internal oblique, and the transversalis.* 

On each side of this line, two long narrow muscles (the recti,) 
are situated between these tendons, and do away the white ap- 
pearance; but exterior to these muscles, the tendons are again 
united, and form a white line on each side, which is called linea 
semilunaris, from its curved shape. 

At the lower part of the tendon, near the os pubis, the fibres 
are so arranged, that they form two bands more firm and dense 
than the rest of the tendon, which are called columns : these 
columns are separated from each other; and the vacuity between 
them is the abdominal ring, or aperture, for the passage of the 
spermatic chord in males and the round ligament of the uterus 
in females. This vacuity or aperture has an oval form, which 
is occasioned by some additional tendinous fibres at the upper 
part of it, that have a transverse direction. 

The uppermost of the two columns is continued obliquely 
downwards, and is inserted into the os pubis of the opposite side, 
near the symphysis, decussating the fibres of the corresponding 
column of that side. 

The lower edge of the tendon of the external oblique is at- 
tached to the superior anterior spinous process of the ilium, and 

* According to Meckel, the linea alba performs the same office in the abdomen 
as the sternum does in the thorax, with this only difference, that it is not formed 
of bone. The anterior tendons of the broad muscles are attached to it, in the 
same way that the cartilages of the ribs are articulated with the sternum, and the 
difference of tissue which exists between it and the sternum is attributable to the 
general difference of structure between the abdominal and pectoral cavities, the 
latter being formed almost entirely of osseous parts, whilst the walls of the former 
are fleshy and tendinous. — p. 



ABDOMINAL MUSCLES. 30 1 

is there blended with the tendinous fascia, which extends down 
the thigh. 

From this process the edge of the tendon is extended, like the 
chord of a bow, across the concavity formed by the os ilium 
and os pubis, and is inserted into the pubis near its symphysis. 
As it proceeds from the spine of the ilium towards the pubis, 
the edge is folded inwards, so that the membrane is doubled. 
The portion which is turned inwards is very small at its com- 
mencement, and continues so for a great part of its extent ; but 
becomes much broader within an inch of its termination. This 
broad extremity is inserted into the small process of the pubis 
near the symphysis, and into a ridge which continues backward 
from the process to the brim of the pelvis, so that the tendinous 
membrane at this part is doubled; the part which is turned back 
being about an inch broad at the place of its insertion into the 
pubis. 

This doubling forms a partial sheath near the pubis for con- 
taining the spermatic chord, and supports it for a short distance 
on the inside of the abdominal ring. 

The edge formed by the fold of the membrane is called Pou- 
parVs ligament, and is very firm and strong ; owing to the mem- 
brane being thicker at that place. The real edge, or termination 
of the portion which is folded inwards, is arranged in the follow- 
ing manner : the part which is nearest to the spine of the ilium 
is continued into the cellular membrane, or the fascia, which is 
between the internal oblique and transversalis muscles, and the 
iliacus internus. 

But the edge of that part which is inserted into the ridge of 
the pubis seems to form a portion of a circular opening, which 
is occupied in part, but not completely, by the crural vessels. 
— This edge of Poupart's ligament, inserted into the ridge or crest 
of the pubis is of a triangular shape, and is called GimbernaV s 
ligament. It is one of the seats of stricture in crural hernia. 
The base of the triangle is towards the symphysis pubis. — 

A portion of the fascia of the thigh, which covers these ves- 
sels, passes under this portion of the tendon, and. is also inserted 
into the ridge of the pubis; so that when the intestines protrude 

vol. i. 26 



302 ABDOMINAL MUSCLES. 

at this aperture, and are strangulated, this portion of the fascia 
of the thigh must also compress them. — This portion of the 
fascia lata femoris, is called the crescentic or falciform portion 
of the fascia lata. The sharp edge at its inner part, by which 
it is nearly continuous with Gimbernat's ligament, and which is 
directed downwards and backwards, is called Hay's ligament or 
the femoral ligament ; it is directly above or in front of the crural 
ring ; that space between the crural vein and Gimbernat's liga- 
ment, included in the sheath of the femoral vessels, and through 
which the viscera protrude in crural hernia. — 

The fascia of the thigh is connected with the external edge, 
or Poupart's ligament, its whole extent : and there is also a fas- 
cia {fascia superficialis abdominis) which covers the whole ten- 
don of the external oblique muscle, and passes from it down 
upon the fascia of the thigh : which also connects the tendon of 
the external oblique to the fascia of the thigh, and serves to bind 
it down. From these connexions it is probable that the tendon 
is in a very different situation before dissection, from what it is 
afterwards ; as the division of these connexions, necessarily 
made by the dissection, renders it much more loose than it could 
have been while the parts were undivided. This structure has 
latterly been called the crural arch.* 

* The fascia which covers the tendon of the external oblique muscle, and de- 
scends upon the thigh, can be examined very easily in anasarcous subjects ; as in 
them, the cellular membrane, which is situated between this fascia and the tendon, 
is somewhat distended by the effused fluid. 

To prepare Poupart's ligament, or the crural arch, for examination, remove care- 
fully the cellular membrane from the tendon of the external oblique, and also from 
the fascia of the thigh, taking care not to remove any part of the fascia which 
passes under the tendon to be inserted into the os pubis. Then make an incision 
in the tendon of the external oblique, about three inches above Poupart's ligament, 
parallel to it, and nearly of the same length ; make a second incision from the up- 
per end of this, to the junction of the aforesaid ligament with the superior ante- 
rior spine of the ilium ; and a third incision from the lower end to the abdominal 
ring. Dissect this flap carefully from the internal oblique, until the spermatic 
chord, the cremaster muscle, and the lower origin of the internal oblique, are 
perfectly uncovered. After examining the internal surface of the tendon and its 
insertion at the pubis, the fascia of the thigh may be dissected, so that its con- 
nexion with the folded edge of the tendon, and its insertion into the pubis, may 
also be examined. 



ABDOMINAL MUSCLES. 303 

The external oblique muscles compress the abdomen, and 
therefore contribute to the evacuation of its contents : if the dia- 
phragm is in a passive state, they force it upwards, by pressing 
the abdominal viscera against it ; and thus assist in producing 
expiration and its various modifications of coughing, sneezing, 
&c. 

They bend the spine forwards, or approach the thorax to the 
pelvis. 

When one acts separately, it bends the trunk obliquely to the 
side on which it is situated. 

3. Obliquus Ascendens Interims, 

Arises from the spine of the ilium the whole length between 
the posterior and superior anterior spinous process ; from the os 
sacrum and the three undermost lumbar vertebrae, by a tendon, 
(fascia lumborum) common to it, to the serratus posticus inferior 
musole, and to the latissimus dorsi ; from Poupart's ligament, at 
the middle of which it sends off the beginning of the cremaster 
muscle ; the spermatic chord in the male, or round ligament 
of the womb in the female, passes under its thin edge, with the 
exception of a few detached fibres. 

Inserted into the cartilago-ensiformis, into the cartilages of 
the seventh, and those of the false ribs ; but, at the upper part, 
it is extremely thin, resembling a cellular membrane, and only 
becomes fleshy at the cartilage of the tenth rib. Here its tendon 
divides into two layers ; the anterior layer, with a great portion 
of the inferior part of the posterior layer, joins the tendon of the 
external oblique, and runs over the rectus to be inserted into the 
whole length of the linea alba. The posterior layer joins the 
tendon of the transversalis muscle as low as half way between 
the umbilicus and os pubis; but, below this place, only a few 
fibres of the posterior layer are seen, and the rest of it passes 
before the rectus muscle, and is inserted into the linea alba ; so 
that the whole tendon of the external oblique muscle, with the 
anterior layer of the internal oblique, passes before the rectus 
muscle; and the whole posterior layer of the internal oblique, 
together with the whole tendon of the transversalis muscle, ex- 



304 



ABDOMINAL MUSCLES. 



cepting at the inferior part, passes behind the rectus, and is in- 
serted into the linea alba. At its undermost part, it is inserted 
into the forepart of the os pubis. 

Fig. 20.* 




Use. To assist the former; but it bends the trunk in the re- 
verse direction. 

3. Transversalis, 
Arises, tendinous, but soon becoming fleshy, from the inner or 
back part of the cartilages of the seven lower ribs, where some 
of its fibres are continued with those of the diaphragm and the 
intercostal muscles; by a broad thin tendon, connected to the 
transverse processes of the last vertebra of the back, and the four 
superior vertebras of the loins ; fleshy, from the whole spine of 
the os ilium internally, and from the tendon of the external ob- 
lique muscle where it intermixes with some fibres of the inter- 
nal oblique. 

* Transverse section of abdomen. — a, Division of the tendon of the internal 
oblique into two layers, forming a sheath in which is contained the rectus muscle. 
b, External oblique, c, Internal oblique, d, Transversalis. e, Between the last 
rib and the crista of the ilium, the fibres of the transversalis, arise from a ten- 
dinous layer, which is trifoliate in its origin, according to Todd. /, The anterior 
division, arising from the roots of the transverse processes, and covering the quad- 
ratus lumborum muscle. h,g, The middle, which is weak, attached to the apices 
of the transverse processes. The posterior is the fascia lumborum. 



ABDOMINAL MUSCLES. 305 

Inserted into the cartilago-ensiformis, and into the whole 
length of the linea alba, excepting its lowermost part. 

Use.- To support and compress the abdominal viscera, and it 
is so particularly well adapted for the latter purpose, that it 
mio-ht be called the proper constrictor of the abdomen. 

The long muscle in the middle is named 

Rectus Abdominis, 

Arises, by two heads, from the ligament of the cartilage which 
joins the two ossa pubis to each other ; runs upwards the whole 
length of, and parallel to the linea alba, growing broader and 
thinner as it ascends. 

Inserted into the cartilages of the three inferior true ribs, and 
often intermixed with some fibres of the pectoral muscle. 

It is generally divided by three tendinous intersections : the 
first is at the umbilicus ; the second, where it runs over the car- 
tilage of the seventh rib; and the third in the middle between 
these ; and there is commonly a half intersection below the um- 
bilicus. These intersections (linece transversce) seldom penetrate 
through the whole thickness of the muscle : they adhere firmly to 
the anterior part of the sheath, bui very slightly to the posterior 
layer.* 

Use. To compress the forepart, but more particularly the low- 
er part of the belly ; to bend the trunk forwards, or to raise the 
pelvis. By its tendinous intersection, it is enabled to contract at 
any of the intermediate spaces ; and, by its connexion with the 
tendons of the other muscles, it is prevented from changing 
place, and from rising into a prominent form when in action. 

The short muscle in the middle is named 

* To obtain an accurate idea of the arrangement of the tendons of the three 
large pair of abdominal muscles, it will be necessary to raise or separate the exter- 
nal oblique muscle and tendon from the internal oblique and its tendon, as far as 
the linea semilunaris, and to separate the internal oblique in the same manner 
from the transversalis ; and then to make an incision in the tendon of the exter- 
nal oblique parallel to the linea alba, and about an inch and a half from it, so as 
to bring the whole of the rectus muscle into view. The structure of the sheath 
which contains the rectus can then be examined. 

26 * 



306 



ABDOMINAL MUSCLES. 



Fig. 21. 



Pyramidalis, 

Arises along with the rectus ; and running upwards within the 
same sheath, is 

Inserted, by an acute termination, near half way between the 
os pubis and umbilicus, into the linea alba and inner edge of the 
rectus muscle. 

As it is frequently wanting in both sides without any inconve- 
nience, its 

Use seems to be, to assist the inferior part of the rectus. 

Muscles about the male Organs of Generation. 

The testicles are said to have a thin muscle common to both. 
and one proper to each. 

The common muscle is called 
the 

Dartos. 
This consists of muscular 
fibres blended with the cellular 
membrane lining the scrotum; 
and therefore this portion of skin 
is capable of being corrugated 
and relaxed in a greater degree 
than the skin in other places. 

The muscle proper to each 
testicle is the 

Cremaster. 

Arises from the internal oblique, 
where a few fibres of that mus- 

* Cremaster, from Sir A. Cooper's work, a, Rectus muscle, b, Descending 
fibres of transversalis. c, The internal oblique, d, Conjoined tendons, e, The 
descending fibres of oblique. /, Point of insertion into the pubis, g, Ascending 
fibres, k, One of the reversed arches. 

The formation of the cremaster, appears to be effected by the testicle in its de- 
scent, (as Scarpa, Cloquet, Cooper, Velpeau, and Todd admit,) for before that takes 
place, the muscle does not exist, according to Cloquet. Prior to the descent, the gu- 
bernaculum testis occupies the inguinal canal, and is covered by the fibres of the 
internal oblique, which adhere to it. When the gubernacular is drawn down, these 
fibres descend with it, forming a series of reversed arches. 




PERINEAL MUSCLES. 



307 



cle intermix with the transversalis, near the juncture of the os 
ilium and pubis, over which part it passes, after having pierced 
the ring of the externus obliquus ; and then it descends upon 
the spermatic chord. 

Inserted into the tunica vaginalis of the testicle, upon which it 
spreads, and is insensibly lost.* 

Use. To suspend and draw up the testicle, and to compress 
it in the act of coition. i 

The penis has three pair of muscles : 

1. Erector Penis, 

Arises, tendinous and fleshy, from the tuberosity of the os 
ischium, and runs upwards, embracing the whole crus of the 
penis. 

Inserted into the strong tendinous membrane that covers the 
corpora cavernosa penis, nearly as far up as the union of these 
bodies. 

Use. To compress the crura penis, by which the blood is 
pushed from it into the forepart of the corpora cavernosa ; and 
the penis is by that means more completely distended. The 
erectores seem, likewise, to keep the penis in its proper direction. 

2. Accelerator Urince seu Ejaculator Serninis, 
Arises, fleshy, from the sphincter ani and membranous part of 

* M. J. Cloquet says, that the scattered fasciculi of this muscle are collected 
after their distribution on the tunica vaginalis, and run up on the inner side of the 
chord, to be inserted into the spine of the pubis. He makes the inference from 
this, that the cremaster is a kind of muscular loop, drawn down by the descent of 
the testicle. I am satisfied that the muscle in robust subjects, frequently exists, 
more or less, after the manner in which he speaks of it ; but, in the emaciated, it 
is very indistinct, as regards such an insertion. In the cases where I have seen 
this insertion into the spine of the pubis, the quantity of muscular fibre has been 
by no means so great there as at its origin. This observation of M. Cloquet's is in- 
genious and interesting, but it is well worthy of consideration, that Mr. John Hun- 
ter's opinion, in his paper on the descent of the testicle, is opposed to it, and on 
the following grounds: in the young ram, and in several other animals, the cre- 
master muscle is formed before the testicle descends from the abdomen into the 
scrotum, being reflected along the gubernaculum testis upwards towards the loins. 
Mr. Hunter could not, it is true, verify the same observation on the human sub- 
ject, but he is disposed, from analogy, to believe that something of the kind ex- 
ists. — H. 



308 



PERINEAL MUSCLES. 



the urethra ; and tendinous, from the crus, nearly as far for- 
wards as the beginning of the corpus cavernosum penis: the 
inferior fibres run more transversely ; and the superior descend, 
in an oblique direction. 

Inserted into a line in the middle of the bulb where it joins 
with its fellow, by which the bulb is completely enclosed. 

Use. To drive the urine or semen forwards ; and, by grasp- 
ing the bulb of the urethra, to push the blood towards the corpus 
cavernosum and the glans, by which these parts are distended. 

. 3. Transversus Perinei, 

Arises from the tough fatty membrane that covers the tube- 
rosity of the os ischium ; from thence it runs transversely in- 
wards, and is 

Inserted into the accelerator urinae, and into that part of the 
sphincter ani which covers the bulb. The place of junction of 
these muscles is called the perineal point or centre. 

Use. To dilate the bulb, and draw the perineum and verge of 
the anus a little outwards and backwards. 

There is often a fourth muscle, named 

Transversus Perinei Alter, 

Arises behind the former, runs more obliquely forwards, and is 
Inserted into that part of the accelerator urinae which covers 
the anterior part of the bulb of the urethra. 
Use. To assist the former. 

In the Medico-Chirurgical Transactions, James Wilson, Esq. F. R. S. 
gives the following account of two small muscles of the membranous part 
of the urethra, viz : Each muscle has a tendon which, at first, is round, but 
soon becomes flattened as it descends. It is affixed to the back part of the 
symphysis pubis, about one-eighth of an inch above the lower edge of the 
cartilaginous arch of the pubes, and nearly at the same distance, below the 
attachment of the tendon of the bladder: to which, and to the tendon of the 
corresponding muscle, it is connected by very loose cellular membrane. The 
tendon descends at first in contact with, and parallel to, its fellow : it soon 
becomes broader, and sends off fleshy fibres, which also increase in breadth, 
and, when near the upper surface of the membranous part of the urethra, 
separate from those of the opposite side, spread themselves on the side of 
the membranous part of the urethra through its whole extent; then fold 



MUSCLES OF THE ANUS. 309 

themselves under it, and meet in a middle tendinous line with similar fibres 
of the opposite side. 

Its action seems to be to draw up the membranous part of the urethra, 
and compress it against the inside of the cartilaginous arch of the pubes ; 
and also to contract the circle round the membranous portion, so as to di- 
minish and even close up the passage for the urine.* 

Muscles of the Anus. 

The anus has a single muscle, and one pair. 
The single muscle is 

Sphincter Jlni. 

Arises from the skin and fat that surrounds the verge of the 
anus on both sides, nearly as far as the tuber of the os ischium ; 
the fibres are gradually collected into an oval form, and surround 
the extremity of the rectum. 

Inserted, before, by a narrow point, into the perineum, acce- 
leratores urinas, and transversi perinei ; behind, by an acute ter- 
mination, into the extremity of the os coccygis. 

Use. Shuts the passage through the anus into the rectum ; 
pulls down the bulb of the urethra, by which it assists in eject- 
ing the urine and semen. — The sphincter ani is always in a 
contracted state, except at the time of the evacuation of the 
fasces. When the sphincter is in a healthy state, it may be 
made by an effort of the will to contract more strongly, but it 
cannot be made to relax. 

— The irritation induced by the accumulation of fasces in the 
rectum, causes it at first to contract more strongly, and the con- 
traction continues till it is overcome, by the increasing effort of 
the muscular fibres of the rectum, and the action of the dia- 
phragm and abdominal muscles. It acts also as an antagonist 
to the levator ani muscle. — 

N. B. The sphincter internus of Albinus and Douglas, is only 

* I have frequently dissected for this muscle, and in only two or three cases 
have been able to satisfy myself of its having an existence distinct from that of 
the Levator Ani. My friend, Mr. Shaw, who occupies a distinguished rank among 
the cultivators of Anatomy in London, admits of this muscle, but says there is 
much difficulty in distinguishing it from the ligament of the urethra, meaning, I 
presume, its triangular ligament. — h. 



310 MUSCLES OF THE ANUS. 

that part of the circular fibres of the muscular coat of the rectum 
which surrounds its extremity. 

Levator Ani, 

Arises from the os pubis within the pelvis, as far up as the 
upper edge of the foramen thyroideum, and joining of the os 
pubis with the os ischium; from the thin tendinous membrane 
that covers the obturator internus and coccygeus muscle, and 
from the spinous process of the os ischium : its fibres run down 
like rays from a circumference to a centre. 

Inserted into the sphincter ani, acceleratores urinae, and ante- 
rior part of the two last bones of the os coccygis ; surrounds the 
extremity of the rectum, neck of the bladder, prostate gland, 
and part of the vesicular seminales ; so that its fibres behind and 
below the os coccygis joining it with its fellow, they together 
very much resemble the shape of a funnel. 

Use. To draw the rectum upwards after the evacuation of 
the faeces, and to assist in shutting it ; to sustain the contents of 
the pelvis, and to help in ejecting the semen, urine, and contents 
of the rectum ; and, perhaps by pressing upon the veins, to con- 
tribute greatly to the erection of the penis. 

— The muscular funnel, formed by the levator ani muscles of 
the two sides is antagonised by the action of the sphincter ani, 
which, by its connexion with the coccyx and perineal centre pre- 
vents its lower extremity from being drawn upwards. 
— When the sphincter is inflamed, and a fluid effused among its 
fibres, as is an occasional occurrence in the bowel complaint of 
children, the sphincter loses its power, and the levator ani mus- 
cles, unopposed, retract ; and thus by everting the lower margin 
of the rectum, contribute mainly to the formation of prolapsus 
ani. — 

Muscles of the Female Organs of Generation, 
The clitoris has one pair. 

Erector Clitoridis, 
Arises from the crus of the os ischium internally, and in its 
ascent covers the crus of the clitoris as far up as the os pubis. 
Inserted into the upper part of the crus and body of the clitoris. 



PERINEAL MUSCLES OF THE FEMALE. 



311 



Use. Draws the clitoris downwards and backwards; and may 
serve to make the body of the clitoris more tense by squeezing 
the blood into it from its cms. 

The vagina has one pair. 

Sphincter Vagince, 

Arises from the sphincter ani, and from the posterior side of the 
vagina, near the perineum ; from thence it runs up the side of 
the vagina, near its external orifice, opposite to the nymphas and 
covers the corpus cavernosum vaginae. 

Inserted into the crus and body or union of the crura clito- 
ridis. 

Use. Contracts the mouth of the vagina, and compresses its 
corpus cavernosum. 

Transversus Perinei, 

Arises, as in the male, from the fatty cellular membrane which 
covers the tuberosity of the os ischium. 

Inserted into the upper part of the sphincter ani, and into a 
white hardish tough substance in the perineum, between the 
lower part of the pudendum and anus. 

Use. To sustain and keep the perineum in its proper place. 

The anus, as in the male, has a single muscle, and one pair. 

Sphincter Ani. 

Arises, as in the male, from the skin and fat surrounding the 
extremity of the rectum. 

Inserted, above, in the white tough substance of the perineum 
{perineal centre) ; and below, into the point of the os coccygis. 

Use. To shut the passage into the rectum ; and, by pulling 
down the perineum, to assist in contracting the mouth of the 
vagina. 

Levator Ani, 

Arises, as in the male, within the pelvis, and descends along 
the inferior part of the vagina and rectum. 

Inserted into the perineum, sphincter ani extremity of the va- 
gina and rectum. 



312 



MUSCLES OF THE ABDOMINAL CAVITY. 



Use. To raise the extremity of the rectum upwards, to con- 
tract the inferior part of the rectum, and to assist in contracting 
and supporting the vagina ; and, perhaps, by pressing on the 
veins, to contribute to the distention of the cells of the clitoris 
and corpus cavernosum of the vagina. 

Muscles situated within the Cavity of the Abdomen. 

These consist of a single Fig. 22.* 

muscle, and four pair. 

Diaphragma. 

This broad thin muscle, 
which makes a complete 
septum between the thorax 
and abdomen, is concave 
below and convex above ; 
the middle of it on each 
side reaching as high with- 
in the thorax of the skele- 
ton as the fourth rib : it is 
commonly divided into two 
portions. 

1. The superior or, 

Greater Muscle of the Dia- 
phragm, 

.Irises, by distinct fleshy 
fibres, from the cartilago-ensiformis, from the cartilages of the 
seventh, and of all the inferior ribs on both sides. The fibres 
from the cartilago-ensiformis, and from the seventh and eighth 

* Thorax of a male. — On the left side the muscles are removed ; on the right 
they are left in situ, a, a, Cervical and lumbar parts of the spinal column, the 
dorsal portion is concealed by the sternum, b. c, c, The true ribs. c\ The false 
ribs, d, The clavicle, e, Intercostal muscles. /, Last false rib, concealed by 
the origin of a part of the greater muscle of the diaphragm, g, The arch formed 
in the interior of the thorax by the diaphragm : the position of this arch on the 
right side, is indicated by a dotted line, h, Columns, or crura of the lesser mus- 
cles of the diaphragm, arising from the lumbar vertebrae, i, Levatores costarum, 
longiores, and breviorcs. 




MUSCLES OF THE ABDOMINAL CAVITY. 3J3 

ribs, run obliquely upwards and backwards ; from the ninth and 
tenth, transversely inwards and upwards, and from the eleventh 
and twelfth, obliquely upwards. From these different origins 
the fibres run, like radii from the circumference to the centre of 
a circle; and are 

Inserted into a cordiform tendon, of a considerable breadth, 
which is situated in the middle of the diaphragm, and in which, 
therefore, the fibres from opposite sides are interlaced. To- 
wards the right side the tendon is perforated, by a triangular 
hole, for the passage of the vena cava inferior; and to the upper 
convex part of it the pericardium and mediastinum are con- 
nected. 

The inferior, lesser muscle, or 

Appendix of the Diaphragm, 

Arises from the second, third and fourth lumbar vertebrae, 
by eight heads, of which, two in the middle, commonly called 
its crura, are the longest, and begin tendinous. Between the 
crura, the aorta and thoracic duct pass; and on the outside of 
these, the great sympathetic nerves and branches of the vena 
azygos perforate the shorter heads. The muscular fibres run 
obliquely upwards and forwards, and form in the middle two 
fleshy columns, which decussate and leave an oval space be- 
tween them for the passage of the oesophagus and eighth pair of 
nerves. 

Inserted, by strong fleshy fibres, into the posterior part of the 
middle tendon. 

Use. The diaphragm is the principal agent in respiration, 
particularly in inspiration : for when it is in action, the fibres, from 
their different attachments, endeavour to bring themselves into a 
plain towards the middle tendon, by which the cavity of the tho- 
rax is enlarged, particularly at the sides, where the lungs are 
chiefly situated ; and as the lungs must always be contiguous to 
the inside of the thorax and upper side of the diaphragm, the air 
rushes into them, in order to fill up the increased space. This 
muscle is assisted by the two rows of intercostals, which elevate 
the ribs, and the cavity of the thorax is more enlarged. In time 

vol. 1. 27 



314 MUSCLES OF THE ABDOMINAL CAVITY. 

of violent exercise, or whatever cause drives the blood with un- 
usual celerity towards the lungs, the pectoral muscles, the ser- 
rati antici majores, the serrati postici superiores, and scaleni 
muscles, are brought into action. These efl'ect the lateral dila- 
tation of the thorax. And in laborious inspiration, the muscles 
which arise from the upper part of the thorax, when the parts 
into which they are inserted are fixed, likewise assist. In expi- 
ration, the diaphragm is relaxed and pushed up by the pressure 
of the abdominal muscles upon the viscera of the abdomen ; 
and at the same time that they press it upwards, they also, to- 
gether with the sterno-costales and serrati postici inferiores, pull 
down the ribs, and are assisted, in a powerful manner, by the 
elasticity of the cartilages that join the ribs to the sternum ; by 
which the cavity of the thorax is diminished, and the air sud- 
denly pushed out of the lungs : and, in laborious expiration, the 
quadrati lumborum, sacro-lumbales, and longissimi dorsi, concur 
in pulling down the ribs. — The diaphragm, contributes the 
principal share to the dilatation of the chest during inspiration. 
When relaxed, the diaphragm is arched, and the top of the arch is 
nearly on a horizontal level with the anterior portion of the fourth 
rib, as seen in Fig. 22, page 312. When contracted, the arch is 
flattened, (though the cordiform tendon itself, is but little depress- 
ed,) and the capacity of the thorax is increased, at the same time 
that the abdominal viscera are pressed downwards, so as to pro- 
duce the protrusion of the abdomen observed during inspiration. 
The abdominal muscles and the diaphragm, usually antagonise 
each other, by contracting alternately. Occasionally they con- 
tract in unison, as in straining during defecation, parturition, &c, 
and compress the viscera and their contents, between the two 
planes which they form, with such force, as to give rise at times 
to hernial protrusions. 

— In natural tranquil inspiration, the dilatation of the chest is ef- 
fected almost wholly by the diaphragm. — 
The four pair are, 

1. Quadratus Lumborum, 

Arises, somewhat broad, tendinous and fleshy, from the poste- 
rior part of the spine of the os ilium. 



MUSCLES OF THE ABDOMINAL CAVITY. 



315 



Inserted into the transverse processes of all the vertebras of 
the loins, into the last rib near the spine, and by a small tendon 
into the side of the last vertebra of the back. 

Use. To move the loins to one side, pull down the last rib, 
and, when both act, to bend the loins forwards. 

2. Psoas Parvus, 

Arises, fleshy, from the sides of the two upper vertebrae of the 
loins, and sends off a small long tendon, which ends thin and flat, 
and is 

Inserted into the brim of the pelvis, at the junction of the os 
ilium and pubis. 

Use. To assist the psoas magnus in bending the loins for- 
wards ; and, in certain positions, to assist in raising the pelvis. 

JV. B. This muscle is very often wanting. 

3. Psoas Magnus, 

Arises, fleshy, from the side of the body and transverse pro- 
cess of the last vertebra of the back ; and, in the same manner, 
from those of the loins, by as many distinct slips. — At its su- 
perior portion, this muscle is covered by a thin fibrous expan- 
sion which is attached on the one hand to the points of the 
transverse processes, and on the other to the bodies of the upper 
lumbar vertebras. This expansion, the arcus interior of Senac and 
Haller, separates the psoas from the diaphragm. On the outer 
side of this is another aponeurotic arch, called ligamentum arcu- 
atum ; it passes from the outer extremity of the former, to the 
inferior margin of the last rib, embracing in its curve below, the 
quadratus lumborum muscle. Both these arches give origin on 
their upper margin to fibres of the lesser muscle of the diaphragm, 
and serve to cut off more effectually any communication between 
the thoracic and abdominal cavities. — 

Inserted, tendinous, into the trochanter minor of the os femo- 
ris ; and fleshy into that bone, a little below the same tro- 
chanter. 

Use. To bend the thigh forwards ; or, when the inferior ex- 
tremity is fixed, to assist in bending the body. 



316 MUSCLES WITHIN THE PELVIS. 

4. Jliacus Interims, 

Arises, fleshy, from the transverse process of the last vertebra 
of the loins, from all the inner lip of the spine of the os ilium, 
from the edge of that bone between its anterior spinous process 
and the acetabulum, and from most of the hollow part of the 
ilium. It joins with the psoas magnus, over the pubis, where it 
begins to become tendinous; and is 

Inserted along with it on the trochanter minor. 

Use. To assist the psoas in bending the thigh, and to bring it 
directly forwards. 

N. B. The insertion of the two last muscles should not be 
traced till the muscles of the thigh are dissected. 

Muscles situated icithin the Pelvis. 
Of these there are two pair. 

1. Obturator Interims, 

Arises from more than one half of the internal circumference 
of the foramen thyroideum, formed by the os pubis and ischium, 
and from the upper part of the plane of the ischium, where it joins 
the ileum. Its inner face is covered by a portion of the levator 
ani; and appears to be divided into a number of fasciculi, which 
unite, and form a roundish tendon, that passes out of the pelvis, 
between the posterior sacro-ischiatic ligament and tuberosity of 
the os ischium ; where it passes over the capsular ligament of 
the thigh bone, it is enclosed as in a sheath, by the gemini mus- 
cles. 

Inserted, by a round tendon, into the large pit at the root of 
the trochanter major. 

Use. To roll the os femoris obliquely outwards. 

JV. B. The insertion of this muscle should not be traced 
until the muscles of the thigh, to which it belongs, are dissected. 

2. Coccygeus. 

Arises, tendinous and fleshy, from the spinous process of the 
os ischium, and covers the inside of the posterior sacro-ischiatic 



MUSCLES OF THE BACK. 317 

ligament ; from this narrow beginning, it gradually increases to 
form a thin fleshy belly, interspersed with tendinous fibres. 

Inserted into the extremity of the os sacrum, and nearly the 
whole length of the os coccygis laterally. 

Use. To support and move the os coccygis forwards, and to 
tie it more firmly to the sacrum. 

Muscles situated on the Posterior Part of the Trunk. 

These may be divided into four layers and a single pair. 
The first layer consists of two muscles, which cover almost 
the whole posterior part of the trunk. 

Trapezius seu Cuculluris, 

Arises, by a strong round tendon, from the lower part of the 
protuberance in the middle of the os occipitis behind; and, by a 
thin membranous tendon, which covers part of the splenitis and 
complexus muscles from the rough curved line that extends 
from the protuberance towards the mastoid process of the tem- 
poral bone; runs down along the nape of the neck, where it 
seems to arise from its fellow, and covers the spinous processes 
of the superior vertebras of the neck ; but rises from the spinous 
processes of the two inferior, and from the spinous processes of 
all the vertebras of the back : adhering tendinous, to its fellow 
the whole length of its origin. 

Inserted, fleshy, into the posterior half of the clavicle ; tendin- 
ous and fleshy, into the acromion, and into almost all the spine 
of the scapula. 

Use. Moves the scapula according to the three different direc- 
tions of its fibres: for the upper descending fibres draw it ob- 
liquely upwards; the middle transverse straight fibres draw it 
directly backwards ; and the inferior ascending fibres draw it 
obliquely downwards and backwards. 

N B. Where it is inseparably united to its fellow in the nape 
of the neck, it is named Ligamentum Nucha, or Colli. — The two 
trapezii taken together, have some resemblance to the monk's 
cowl hanging over the neck, hence the name of cucullares given 
to them. — 

27* 



318 MUSCLES OF THE BACK. 

2. Latissimus Dorsi, 

Arises, by a broad thin tendon, from the posterior part of the 
spine of the os ilium, from all the spinous processes of the os 
sacrum and vertebras of the loins, and from the seven inferior 
ones of the vertebras of the back; also tendinous and fleshy, 
from the extremities of the three or four inferior ribs, a little 
beyond their cartilages, by as many distinct slips. The inferior 
fibres ascend obliquely, and the superior run transversely, over 
the inferior angle of the scapula, towards the axilla where they 
are collected, twisted, and folded. —Sometimes a few additional 
fibres of the muscle, arise from the inferior angle of the sca- 
pula. — 

Inserted, by a strong thin tendon, into the inner edge of the 
groove for lodging the tendon of the long head of the biceps. 

Use. To pull the arm backwards and downwards, and to roll 
the os humeri. 

N. B. The insertion of this muscle should not be prosecuted 
till the muscles of the os humeri, to which it belongs, are dis- 
sected. 

The second layer consists of three pair, two on the back, and 
one on the neck. 
On the back : 

1. Serratus Posticus Inferior, 
Arises, by a broad thin tendon, in common with that of the 
latissimus dorsi, from the spinal process of the two inferior ver- 
tebras of the back, and from the three superior vertebras of the 
loins. 

Inserted into the lower edge of the four inferior ribs, at a lit- 
tle distance from their cartilages, by as many distinct fleshy slips. 
Use. To depress the ribs into which it is inserted. 

2. Rhomboideus. 
This muscle is divided into two portions. 
1. Rhomboideus major, arises, tendinous, from the spinous pro- 
cesses of the five superior vertebras of the back. 

Inserted into all the basis of the scapula below its spine. 



MUSCLES OF THE BACK. 



319 



Use. To draw the scapula obliquely upwards, and directly in- 
wards. 

2. Rhomboideus minor, arises, tendinous, from the spinous pro- 
cesses of the three inferior vertebras of the neck, and from the 
ligamentum nuchas. 

Inserted into the base of the scapula, opposite to its spine. 

Use. To assist the former. 

On the neck: 

3. Splenitis, 

Arises, tendinous, from the four superior spinous processes 
of the vertebras of the back : tendinous and fleshy, from the five 
inferior of the neck, and adheres firmly to the ligamentum 
nuchas. At the third vertebra of the neck, the splenii recede 
from each other, so that part of the complexus muscle is seen. 

Inserted, by as many tendons, into the five superior transverse 
processes of the vertebras of the neck ; and tendinous and fleshy, 
into the superior part of the mastoid process, and into the os oc- 
cipitis, where it joins with the root of that process. 

Use. To bring the head and upper vertebras of the neck back- 
wards laterally : and, when both act, to pull the head directly 
backwards. 

./V. B. Albinus divides this muscle into two, viz. That por- 
tion which arises from the five inferior spinous processes of the 
neck, and is inserted into the mastoid process and os occipitis, 
he calls splenitis capitis ; and that portion which arises from the 
third and fourth of the back, and is inserted into the five superior 
transverse processes of the neck, is called by him splenitis colli. 

The single pair, 

Serratus Superior Posticus, 

Arises, by a broad thin tendon, from the spinous processes of the 
three last vertebras of the neck, and the two uppermost of the back. 

Inserted into the second, third, fourth, and fifth ribs, by as 
many fleshy slips. 

Use. To elevate the ribs, and dilate the thorax. 

The third layer consists of three pair on the back, and three 
on the neck. 

Those on the back are, 



320 MUSCLES OF THE BACK. 

1. Spi?ialis Do?'si, 

Arises from the spinous processes of the two uppermost verte- 
brae of the loins, and the three inferior of the back, by as many 
tendons. 

Inserted into the spinous processes of the nine uppermost ver- 
tebras of the back, except the first, by as many tendons. 

Use. To erect and fix the vertebrae, and to assist in raising the 
spine. 

2. Longissimus Dorsi, 

Arises, tendinous without, and fleshy within, from the side, 
and all the spinous processes of the os sacrum ; from the posterior 
spine of the os ilium ; from all the spinous processes, and from 
the roots of the transverse processes of the vertebrae of the loins. 

Inserted into all the transverse processes of the vertebrae of 
the back, chiefly by small double tendons ; also, by a tendinous 
and fleshy slip, into the lower edge of all the ribs, except the two 
inferior, at a little distance from their' tubercles. 

Use. To extend the vertebrae, and to raise and keep the trunk 
of the body erect. 

JV. B. From the upper part of this muscle, there runs up a 
round fleshy portion which joins with the cervicalis descendens. 

3. Sacro-Lumbalis, 

Arises, in common with the longissimus dorsi. 

Inserted into all the ribs, where they begin to be curved for- 
wards, by as many long and thin tendons ; and, 

From the upper part of the six or eight lower ribs, arise as 
many bundles of thin fleshy fibres, which soon terminate in the 
inner side of this muscle, and are named musculi ad sacro-hm- 
balem accessorii. 

Use. To pull the ribs down, and assist in erecting the trunk of 
the body. 

JV. B. There is a fleshy slip which runs from the upper part 
of this muscle into the fourth, fifth, and sixth transverse pro- 
cesses of the vertebrae of the neck, by three distinct tendons : it 
is named cervicalis descendens ; and its use is to turn the neck 
obliquely backwards, and to one side. 



MUSCLES OF THE BACK AND NECK 321 

On the neck are, 

1. Cofnplexus, 

Arises from the transverse processes of the seven superior 
vertebrae of the back, and four inferior of the neck, by as many 
distinct tendinous origins ; in its ascent, it receives a fleshy slip 
from the spinous process of the first vertebra of the back. From 
these different origins it runs upwards, and is every where inter- 
mixed with tendinous fibres. 

Inserted, tendinous and fleshy, into the inferior edge of the 
protuberance in the middle of the os oocipitis, and into a part of 
the curved line that runs forwards from that protuberance. 

Use. To draw the head backwards, and to one side, and when 
both act, to draw the head directly backwards. 

JV! B. The long portion of this muscle that is situated next 
the spinous processes, lies more loose, and has. a roundish ten- 
don in the middle of it : for which reason Albinus calls it biven- 
ter cervicis. 

2. Trachelo-Mastoideus, 

Arises from the transverse processes of the three uppermost 
vertebrae of the back, and from the five lowermost of the neck, 
(where it is connected to the transversalis cervicis,) by as many 
thin tendons, which unite into a belly, and run up under the 
splenius. 

Inserted into the middle of the posterior side of the mastoid 
process, by a thin tendon. 

Use. To assist the complexus ; but it pulls the head more to 
one side. 

3. Levator Scapula, 

Arises, tendinous and fleshy, from the transverse processes of 
the five superior vertebrae of the neck, by as many distinct slips, 
which soon unite to form a muscle that runs downwards and 
outwards. 

Inserted, fleshy, into the superior angle of the scapula. 

Use. To pull the scapula upwards and a little forwards. 

The fourth layer consists of two pair on the back, two on the 
posterior part of the neck, four small pair situated immediately 



JJ22 MUSCLES OF THE BACK AND NECK. 

below the posterior part of the occiput, and three on the side of 
the neck. 

On the back are, 

1. Semi-Spinalis Dorsi, 

Arises, from the transverse processes of the seventh, eighth, 
ninth, and tenth vertebras of the back, by as many distinct tendons, 
which soon grow fleshy, and then become tendinous; and are 

Inserted into the spinous processes of all the vertebra; of the 
back above the eighth, and into the two lowermost of the neck, 
by as many tendons. 

Use. To extend the spine obliquely backwards. 

2. Multifidus Spines, 

Arises from the side and spinous processes of the os sacrum, 
and from the posterior part of the os ilium, where it joins with 
the sacrum; from all the oblique and transverse processes of the 
vertebras of the loins; from all the transverse processes of the 
vertebras of the back, and from those of the neck, except the three 
first, by as many distinct tendons, which soon grow fleshy, run 
in an oblique direction; and are 

Inserted, by distinct tendons, into all the spinous processes of 
the vertebras of the loins, of the back, and of the neck, except the 
first. 

Use. When the different portions of this muscle act on one side, 
they extend the back obliquely, or move it laterally ; but if they 
act together on both sides, they extend the vertebras backwards. 

On the posterior part of the neck are, 

1. Semi-Spinalis Colli, 

Arises from the transverse processes of the uppermost six 
vertebras of the back, by as many distinct tendons ascending 
obliquely under the complexus. 

Inserted into the spinous processes of all the vertebras of the 
neck, except the first and the last. 

Use. To extend the neck obliquely backwards. 

2. Transversalis Colli, 

Arises from the transverse processes of the five uppermost 



MUSCLES OF THE BACK AND NECK. 333 

vertebras of the back, by as many tendinous and fleshy origins; 
runs between the trachelo mastoideus, and splenius colli and 
cervicalis descendens. 

Inserted into the transverse processes of all the cervical verte- 
bra;, except the first and the last. 

Use. To turn the neck obliquely backwards, and a little to one 
side. 

Below the posterior part of the occiput are. 

1. Rectus Capitis Posticus Major, 

Arises, fleshy, from the external part of the spinous process of 
the second vertebra of the neck, and grows broader in its as- 
cent, which is not straight, but obliquely outwards. 

Inserted, tendinous and fleshy, into the os occipitis, near the 
rectus capitis lateralis, and the insertion of the obliquus capitis 
superior. 

Use. To pull the head backwards, and to assist a little in its 
rotation. 

2. Rectus Capitis Posticus Minor, 

Arises, by a narrow beginning, close to its fellow, from a little 
protuberance in the middle of the back part of the first vertebra 
of the neck, its outer edge being covered by the rectus major. 

Inserted, somewhat broad, into the sides of a dimple in the os 
occipitis, near its foramen magnum. 

Use. To assist the rectus major in moving the head backwards. 

3. Obliquus Capitis Superior, 

Arises from the transverse process of the first vertebra of the 
neck. 

Inserted, tendinous and fleshy, into the os occipitis behind the 
back part of the mastoid portion of the temporal bone, and under 
the insertion of the complexus muscle. 

Use. To draw the head backwards. 

4. Obliquus Capitis Inferior, 

Arises, fleshy, from the spir.ous process of the second vertebra 
of the neck, its whole length ; and, forming a thick fleshy belly, is 



324 MUSCLES OF THE BACK AND NECK. 

Inserted into the transverse process of the first vertebra of the 
neck. 

Use. To give a rotary motion to the head. 
On the side of the neck are, 

1. Scalenus Anticus, 

Arises from the fourth, fifth, and sixth transverse processes of 
the first vertebra of the neck, by as many tendons. 

Inserted, tendinous and fleshy, into the upper side of the first 
rib near its cartilage. 

2. Scalenus Medius, 

Arises from all the transverse processes of the vertebras of the 
neck, by as many strong tendons; the nerves to the superior ex- 
tremity pass between it and the former. 

Inserted into the upper and outer part of the first rib, from its 
root, to within the distance of an inch from its cartilage. 

3. Scalenus Posticus, 

Arises from the fifth and sixth transverse processes of the 
vertebras of the neck. 

Inserted, into the upper edge of the second rib, not far from 
the spine. 

Use of the three scaleni: to bend the neck to one side ; or, when 
the neck is fixed, to elevate the ribs, and to dilate the thorax. 

There are a number of small muscles situated between the 
spinous and transverse processes of contiguous vertebras; which 
are accordingly named, 

1. Interspinales Colli. 

The space between the spinous processes of the vertebras of 
the neck, most of which are bifurcated, is filled up with fleshy 
portions; each of which 

Arises, double, from the spinous processes of the cervical ver- 
tebras below, and ascends to be 

Inserted, in the same manner, into the spinous process of the 
vertebras above. Thev are five in number. 



MUSCLES OF THE SUPERIOR EXTREMITIES. 325 

Use, To draw these processes nearer to each other. 

2. Intertransversales Colli. 

They begin from the transverse process of the first vertebra 
of the back, and fill up the spaces between the transverse pro- 
cesses of the vertebras of the neck, which are likewise bifurcated; 
and, consequently, there are six distinct double muscles, which 

Arise from the inferior transverse process of each vertebra of 
the neck, and first of the back, and are 

Inserted into the superior transverse processes. 

Use. To draw these processes towards each other, and turn the 
neck a little to one side, 

Inter spinales Dorsi et Lumbor urn, and the Intertransversales Dorsi, 

Are rather small tendons than muscles, serving to connect the 
spinal and transverse processes. 

Intertransversales Lumborum, 

Are four distinct small bundles of flesh, which fill up the space 
between the transverse processes of the vertebras of the loins, 
and serve to draw them towards each other. 



MUSCLES OF THE SUPERIOR EXTREMITIES. 

These may be divided into the muscles that are situated on the 
scapula, on the os humeri, on the cubit or forearm, and on the 
hand. 

Muscles situated on the Scapula. 

These are called muscles of the os humeri; and are three behind, 
one along its inferior costa, two before, and one beneath it. 
Behind are, 

1. Supra- spinatus, 

Arises, fleshy, from all that part of the base of the scapula that 
is above its spine ; also from the spine and superior costa ; passes 
vol. 1. 28 



326 MUSCLES SITUATED ON THE SCAPULA. 

under the acromion, and adheres to the capsular ligament of the 
os humeri. 

Inserted, tendinous, into that part of the large protuberance on 
the head of the os humeri, that is next the groove for lodging the 
tendon of the long head of the biceps. 

Use. To raise the arm upwards; and, at the same time to pull 
the capsular ligament from between the bones, that it may not be 
pinched. 

2. Infraspinatus, 

Arises, fleshy, from all that part of the base of the scapula that 
is between its spine and inferior angle ; and from the spine as far 
as the cervix of the scapula. The fibres ascend and descend ob- 
liquely towards a tendon in the middle of the muscle, which runs 
forwards, and adheres to the capsular ligament. 

Inserted, by a thick and short tendon, into the upper and 
middle part of the large protuberance on the head of the os 
humeri. 

Use. To roll the humerus outwards : to assist in raising, and 
in supporting it when raised ; and to pull the ligament from 
between the bones. 

N. B. These two muscles are covered with a tendinous mem- 
brane, from which a number of their fleshy fibres arise. It serves 
besides to strengthen their actions, and keeps them from swelling 
too much outwardly when in action. 

3. Teres Minor, 

Arises, fleshy, from all the round edge of the inferior costa of 
the scapula, and runs forwards along the inferior edge of the 
infra-spinatus muscle, and adheres to the ligament. 

Inserted, tendinous, into the back part of the large protuberance 
on the head of the os humeri, a little behind and below the ter- 
mination of the last named muscle. 

Use. To roll the humerus outwards, to draw the humerus back- 
wards; and to prevent the ligament from being pinched between 
the bones. 

Along the inferior costa of the scapula is, 



MUSCLES SITUATED ON THE SCAPULA. 307 

Teres Major, 

Arises, fleshy, from the inferior angle of the scapula, and from 
all that portion of its inferior costa that is rough and thicker 
than the rest ; its fleshy fibres are continued over part of the 
infra-spinatus muscle, to which they firmly adhere. 

Inserted, by a broad, short, and thin tendon, into the ridge at 
the inner side of the groove for lodging the tendon of the long 
head of the biceps, along with the latissimus dorsi. 

Use. To roll the humerus inwards, and to draw it backwards 
and downwards. 

The two before the scapula are, 

1. Deltoides, 

Arises, fleshy, from all the posterior part of the clavicle that 
the pectoralis major does not occupy; tendinous and fleshy, from 
the acromion, and lower margin of almost the whole spine of 
the scapula opposite to the insertion of the cucullaris muscle : 
from the origins it runs in three different directions, i. e. from 
the clavicle outwards and downwards ; from the spine of the 
scapula outwards, forwards, and downwards; and from the 
acromion, straight downwards ; and is composed of a number 
of fasciculi, which form a strong fleshy muscle that covers the 
anterior part of the joint of the os humeri. 

Inserted, tendinous into a rough protuberance in the outer side 
of the os humeri, near its middle, where the fibres of this muscle 
intermix with some part of the brachialis externus. 

Use. To pull the arm directly outwards and upwards, and a 
little forwards or backwards, according to the different direc- 
tions of its fibres. 

2. Coraco-Brachialis, 

Arises, tendinous and fleshy, from the forepart of the coracoid 
process of the scapula ; adhering in its descent, to the short head 
of the biceps. 

Inserted, tendinous and fleshy, about the middle of the internal 
part of the os humeri, near the origin of the third head of the 



328 MUSCLES SITUATED ON THE OS HUMERI. 

triceps, called brackialis externus, where it sends down a thin 
tendinous expansion to the internal condyle of the os humeri. 

Use. To raise the arm upwards and forwards. 

N. B. There passes a nerve through this muscle, called mus- 
culo culaneus. 

The one beneath the scapula is, 

Subscapularis, 

Arises, fleshy, from all the base of the scapula, internally, and 
from its superior and inferior costae, being composed of a num- 
ber of tendinous and fleshy fasciculi, which make prints on the 
bone; they all join together, fill up the hollow of the scapula, 
and pass over the joint, adhering to the capsular ligament. 

Inserted, tendinous, into the upper part of the internal protu- 
berance at the head of the os humeri. 

Use. To roll the humerus inwards, and to draw it to the side 
of the body ; and to prevent the capsular ligament from being 
pinched. 

Muscles situated on the Os Humeri. 
These are called 

Muscles of the Cubit or Forearm. 

They consist of two before, and two behind. 
Before are, 

1. Biceps Flexor Cubiti, 

Arises, by two heads. The first and outermost called longus, 
begins tendinous from the upper edge of the glenoid cavity of 
the scapula, passes over the head of the os humeri within the 
joint; and, in its descent without the joint, is enclosed in a 
groove near the head of the os humeri, by a membranous liga- 
ment that proceeds from the capsular ligament and adjacent ten- 
dons. The second or innermost head, called brevis, arises ten- 
dinous and fleshy, from the coracoid process of the scapula, in 
common with the coraco-brachialis muscle. A little below the 
middle of the forepart of the os humeri, these heads unite. 



MUSCLES SITUATED ON THE OS HUMERI 329 

Inserted, by a strong roundish tendon, into the tubercle on the 
upper end of the radius internally. 

Use. To turn the hand supine, and to bend the forearm. 

JV. B. At the bending of the elbow, where it begins to grow 
tendinous, it sends off an aponeurosis which covers all the mus- 
cles on the inside of the forearm, and joins with another tendin- 
ous membrane, which is sent off' from the triceps extensor cubiti, 
and covers all the muscles on the outside of the forearm, and a 
number of the fibres, from opposite sides, decussate each other. 
It serves to strengthen the muscles, by keeping them from swell- 
ing too much outwardly, when in action; and a number of their 
fleshy fibres take their origin from it. 

2. Brachialis Internus, 

Arises, fleshy, from the middle of the os humeri, at each side 
of the insertion of the deltoid muscle, covering all the inferior 
and forepart of this bone, runs over the joint and adheres firmly 
to the ligament. 

Inserted, by a strong tendon, into the coronoid process of the 
ulna. 

Use. To bend the forearm, and to prevent the capsular liga- 
ment of the joint from being pinched. 

Behind, are 

1. Triceps Extensor Cubiti, 

Arises, by three heads; the first called long us, somewhat broad 
and tendinous, from the inferior costa of the scapula, near its 
cervix. The second head, called brevis, arises by an acute, ten- 
dinous, and fleshy beginning, from the back part of the os hu- 
meri, a little below its head, outwardly. The third, called bra- 
chialis externus, arises by an acute beginning, from the back 
part of the os humeri. These three heads unite lower than the 
insertion of the teres major, and cover the whole posterior part 
of the humerus, from which they receive addition in their de- 
scent. 

Inserted into the upper and external part of the process of the 

28* 



330 MUSCLES ON THE ANTERIOR PART OF THE FOREARM. 

ulna, called olecranon, and partly into the condyles of the os hu- 
meri, adhering firmly to the ligament. 
Use. To extend the forearm. 

2. Anconeus, 

Arises, tendinous, from the posterior part of the external con- 
dyle of the os humeri ; it soon grows fleshy, and is continued 
from the third head of the triceps. 

Inserted, fleshy, and thin into a ridge on the outer and poste- 
rior edge of the ulna, being continued some way before the ole- 
cranon, and covered with a tendinous membrane. 

Use. To assist in extending the forearm. 

Muscles situated on the Forearm. 

These may be divided into three classes, viz. 

1. The muscles which bend and extend the wrist, and of course the whole 
hand. 

2. Those which bend and extend the fingers exclusively. 

3. Those which act on the radius so as to roll it backwards and forwards 
on the ulna; which are called supinators and pronators. 

The flexors both of the wrist and fingers, and the pronators, lie on the 
front of the forearm. The extensors and the supinators on the back. 

The flexors generally originate from the internal condyle of the os hu- 
meri, and the parts adjacent to it ; the extensors from the external con- 
dyle of the same bone, and the parts which are near it. 

In the following description they are arranged in the order in which they 
occur in the dissection of the arm; beginning with those which origi- 
nate with the internal condyle, without regard to their particular func- 
tions. 

Muscles on the anterior part of the Forearm. 

1. Palmaris Longus, 

Arises, tendinous, from the internal condyle of the os humeri, 
soon grows fleshy, and, after a short progress, sends off a long 
slender tendon. 

Inserted into the ligamentum carpi annulare, and into a ten- 
dinous membrane that is expanded on the palm of the hand, 
named aponeurosis palmaris; which, above, begins at the trans- 



MUSCLES ON THE ANTERIOR PART OP THE FOREARM. 33 j[ 

verse or annular ligament of the wrist, and, below, is fixed to 
the roots of the fingers. 

Use. To bend the hand, and to stretch the membrane that is 
expanded on the palm. 

N. B. This muscle is sometimes wanting, but the aponeurosis 
palmaris is always to be found. 

2. Pronator Radii Teres, 

Arises, fleshy, from the internal condyle of the os humeri, and 
tendinous from the coronoid process of the ulna. 

Inserted, thin, tendinous, and fleshy, into the middle of the 
posterior part of the radius. 

Use. To roll the radius, together with the hand, inwards. 

3. Flexor Carpi Radialis, 

Arises, tendinous and fleshy, from the internal condyle of the 
os humeri, and from the anterior part of the upper end of the 
ulna, where it firmly adheres to the pronator radii teres. 

Inserted, by a flat tendon, into the fore and upper part of the 
metacarpal bone that sustains the forefinger, after running through 
a fossa in the os trapezium. 

Use. To bend the hand, and to assist in its pronation. 

4. Flexor Carpi Ulnaris, 

Arises, tendinous, from the internal condyle of the os humeri. 
It has, likewise, a small fleshy beginning from the outer side of 
the olecranon, between which, and the origin from the condyle, 
there is a space left, through which the ulnar nerve passes to the 
forearm ; and a number of its fleshy fibres arise from the tendi- 
nous membrane that covers the forearm. 

Inserted, by a short strong tendon, into the os pisiforme. At a 
little distance from its insertion, a small ligament is sent off to 
the metacarpal bone that sustains the little finger. 

Use. To assist the former in bending the arm. 

5. Flexor Sublimis Perforatus, 
Arises, tendinous and fleshy, from the internal condyle of the 



332 MUSCLES ON THE ANTERIOR PART OF THE FOREARM 

os humeri; tendinous from the coronoid process of the ulna, 
near the edge of the cavity that receives the head of the radius; 
fleshy from the tubercle of the radius ; and membranous and 
fleshy from the middle of the forepart of the radius, where the 
flexor pollicis longus arises. Its fleshy belly sends off four round 
tendons before it passes under the ligament of the wrist. 

Inserted into the anterior and upper part of the second bone 
of each finger, being near the extremity of the first bone, di- 
vided for the passage of the perforans. 

Use. To bend the second joint or phalanx of the fingers. 

6. Flexor Profundus Perforans, 

Arises, fleshy, from the external side, and upper part of the 
ulna, for some way downwards, and from a large share of the 
interosseous ligament. It splits into four tendons, a little be- 
fore it passes under the ligamentum carpi annulare ; and these 
pass through the slits in the tendons of the flexor sublimis. 

Inserted into the fore and upper part of the third or last bone 
of all the four fingers. 

( \ ■. To bend the last joint of the fingers. 

7. Flexor Longus Pollicis Manus, 

Ai'ises, by an acute fleshy beginning, from the upper part of 
the radius, immediately below its tubercle, and is continued down 
for some space on the forepart of this bone. It has likewise 
generally another origin from the internal condyle of the os hu- 
meri, which forms a distinct fleshy slip, that terminates near the 
upper part of the origin from the radius. 

Inserted into the last joint of the thumb, after having passed 
its tendon under the ligament of the wrist. 

Use. To bend the last joint of the thumb.* 

* The thumb ins but one flexor muscle on the front of the arm, although it has 
three extensors on the back part. — No animal but man has a distinct flexor lon- 
gus pollicis muscle. In the monkey even, its place is supplied by a branch of the 
communis digitorum tendon; man only can bring the thumb in direct opposition 
to the fingers, and make the hand a perfect instrument of prehension. — p. 



MUSCLES ON THE BACK OF THE FOREARM. 333 

8. Pronator Radii Quadratics, 

Arises, broad, tendinous, and fleshy from the lower and inner 
part of the ulna ; the fibres run transversely, to be 

Inserted into the lower and anterior part of the radius, oppo- 
site to its origin. 

Use. To turn the radius, together with the hand, inwards. 

Muscles of the External Side and Back of the Arm. 

1. Supinator Radii Longus, 

Arises, by an acute and fleshy origin, from the external ridge 
of the os humeri, above the external condyle, nearly as far up 
as the middle of that bone. 

Inserted into the outer side of the inferior extremity of the 
radius. 

Use. To roll the radius outwards, and consequently the palm 
of the hand upwards. 

2. Extensor Carpi Radialis Longior, 

Arises, broad, thin, and fleshy, immediately below the supina- 
tor radii longus, from the lower part of the external ridge of the 
os humeri, above its external condyle. 

Inserted, by a round tendon, into the posterior and upper part 
of the metacarpal bone that sustains the fore-finger. 

Use. To extend and bring the hand backwards. 

3. Extensor Carpi Radialis Brevior, 

Arises, tendinous, from the external condyle of the os humeri, 
and from the ligament that connects the radius to it, and runs 
along the outside of the radius. 

Inserted, by a round tendon, into the upper and back part of 
the metacarpal bone that sustains the middle finger. 

Use. To assist the last mentioned muscle. 

4. Extensor Carpi Ulnaris, 
Arises, tendinous from the external condyle of the os humeri, 



304 MUSCLES ON THE BACK OF THE FOREARM 

and in its progress, fleshy, from the middle of the ulna, where 
it passes over the ulna. Its round tendon is enclosed by a mem- 
branous sheath, in a groove which is situated at the extremity of 
the ulna. 

Inserted, by its round tendon, into the posterior and upper 
part of the metacarpal bone that sustains the little finger. 

Use. To assist the former in extending the hand. 

5. Extensor Digitorum Communis, 
Arises, by an acute, tendinous, and fleshy beginning, from 
the external condyle of the os humeri, where it adheres to the 
supinator radii brevis. Before it passes under the ligamentum 
carpi annulare externum, it splits into four tendons; some of 
which may be divided into several smaller ; and about the fore- 
part of the metacarpal bones they remit tendinous filaments to 
each other. 

Inserted into the posterior part of all the bones of the four fin- 
gers, by a tendinous expansion. 

Use, To extend all the joints of the fingers. 

6. Supinator Radii Brevis, 

Arises, tendinous, from the external condyle of the os humeri : 
tendinous and fleshy, from the external and upper part of the 
ulna, and adheres firmly to the ligament that joins these two 
bones. 

Inserted, into the head, neck, and tubercle of the radius, near 
the insertion of the biceps, and into the ridge running from that 
downwards and outwards. 

Use. To roll the radius outwards, and so bring the hand 
supine. 

7. Indicator, 

Arises, by an acute fleshy beginning, from the middle of the 
posterior part of the ulna ; its tendon passes under the same 
ligament with the extensor digitorum communis, with part of 
which it is 

Inserted into the posterior part of the fore-finger. 

Use. To extend the fore-finger separately. 



MUSCLES ON THE PALM OF THE HAND ggg 

8. Extensor Ossis Metacarpi Pollicis Manus, 

Arises, fleshy, from the middle and posterior part of the ulna, 
immediately below the insertion of the anconeus muscle, from 
the posterior part of the middle of the radius, and from the in- 
terosseous ligament. 

Inserted, generally by two tendons, into the os trapezium, and 
upper back part of the metacarpal bone of the thumb, and often 
joins with the adductor pollicis. 

Use. To extend the metacarpal bone of the thumb, outwardly. 

9. Extensor Prirni Internodii, {Ext. Major Pollicis Manus,) 

Arises, fleshy, from the posterior part of the ulna near the 
former muscle, and from the interosseous ligament. 

Inserted, tendinous, into the posterior part of the first bone ot 
the thumb ; and a part of it may be traced as far as the second 
bone. 

Use. To extend the first bone of the thumb obliquely out- 
wards. 

10. Extensor Secundi Internodii, (Ext. Minor Pollicis Manus,) 

Arises, by an acute, tendinous, and fleshy beginning, from the 
middle back part of the ulna, and from the interosseous liga- 
ment ; its tendon runs through a small groove at the inner and 
back part of the lower end of the radius. 

Inserted into the last bone of the thumb. 

Use. To extend the last joint of the thumb obliquely back- 
wards. 

Muscles on the Palm of the Hand. 

To obtain a full view of the muscles situated on the palm of the hand, it 
will be necessary to remove the annular or transverse ligament, which is 
stretched across from the projecting points of the pisiform and unciform 
bones on the inside of the wrist to the scaphoid and trapezium on the 
outside ; for the purpose of retaining the tendons of the flexor muscles in 
their proper situation. And also, to remove from the palm of the hand 
the aponeurosis palmaris, which has been described with the palmaris 
lonmis muscle. 



X$Q MUSCLES ON THE PALM OF THE HAND. 

1. Palmaris Brevis, 

Arises from the ligamentum carpi annulare, and tendinous 
membrane that is expanded on the palm of the hand. 

Inserted, by small bundles of fleshy fibres, into the skin and 
fat that covers the adductor minimi digiti, and into the os pisi- 
forme. 

Use. To assist in contracting the palm of the hand. 

2. Adductor Pollicis Manus, 

Arises, by a broad tendinous, and fleshy beginning, from the 
ligamentum carpi annulare, and from the os trapezium. 

Inserted, tendinous, into the outer side of the root of the first 
phalanx of the thumb. 

Use. To draw the thumb from the fingers. 

3. Flexor Osiss Metacarpi Pollicis, or Opponens Pollicis, 

Arises, fleshy, from the os trapezium and ligamentum carpi 
annulare, lying under the adductor pollicis. 

Inserted, tendinous and fleshy, into the under and anterior 
part of the metacarpal bone of the thumb. 

Use. To bring the thumb inwards, opposite to the other finger. 

4. Flexor Brevis Pollicis Manus, 

Is divided into two portions by the tendon of the flexor longus 
pollicis, and is placed beneath the adductor, and at the side of 
the opponens. It is divided into two heads. The first arises 
fleshy from the volar sides of the trapezium, trapezoides, and 
from the contiguous part of the internal surface of the annular 
ligament. The second head arises from the magnum, unciforme, 
and from the base of the metacarpal bone of the middle finger. 

Inserted, by the first head into the outer sesamoid bone, and 
by the second into the inner sesamoid bones. These bones act 
the parts of patellae, by having a tendinous connexion with the 
first phalanx of the thumb. 

Use. To bend the first joint of the thumb. 



MUSCLES ON THE PALM OF THE HAND. 



337 



5. Abductor Pollicis Manus, 

Arises, fleshy, from almost the whole length of the metacar- 
pal bone that sustains the middle finger ; from thence its fibres 
are collected together. 

Inserted, tendinous, into the inner part of the root of the first 
phalanx of the thumb. 

Use. To pull the thumb towards the fingers. 

There are four small flexors, called, from their form, 

6. Lumbricales, 

Which arise, thin and fleshy, from the outside of the tendons 
of the flexor profundus, a little above the lower edge of the liga- 
mentum carpi annulare. 

Inserted, by long slender tendons, into the outer sides of the 
broad tendons of the interossei muscles, about the middle of the 
first joint. 

Use. To increase the flexion of the fingers while the long 
flexors are in full action. 

7. Adductor Metacarpi Minimi Digiti Manus, 

Arises, fleshy from the thin edge of the os unciforme, and 
from that part of the ligament of the wrist next to it. 

Inserted, tendinous, into the inner side and anterior part of 
the metacarpal bone of this finger. 

Use. To bend and bring the metacarpal bone of this finger 
towards the wrist. . 

8. Flexor Parvus Minimi Digiti, 

Arises, fleshy, from the outer side of the os unciforme, and 
from the ligament of the wrist which joins with that bone. 

Inserted, by a roundish tendon, into the inner and anterior 
part of the upper end of the first bone of this finger. 

Use. To bend the little finger, and assist the adductor. 
vol. i. 29 



338 MUSCLES ON THE PALM OF THE HAND. 

9. Abductor Minimi Digiti Manus, 

Arises, fleshy, from the os pisiforme, and from that part of the 
ligamentum carpi annulare next it. 

Inserted, tendinous, into the inner side of the upper end of the 
first bone of the little finger. 

Use. To draw this finger from the rest. 

The spaces between the metacarpal bones are occupied by 
muscles, called, from their situation, interosseous. The four fol- 
lowing are to be seen on the palm of the hand. 

Anterior Interosseous Muscles. 
1. Prior Indicts, 

Arises, tendinous and fleshy, from the upper and outer part ol 
the metacarpal bone that sustains the fore-finger. 

Inserted into the outside of that part of the tendinous expan- 
sion from the extensor digitorum communis, which covers the 
posterior part of the fore-finger. 

Use. To draw the fore-finger outwards towards the thumb, 
and extend it obliquely. 

2. Posterior Indicis, 

Arises, tendinous and fleshy, from the root and inner part ot 
the metacarpal bone that sustains the fore-finger. 

Inserted into the inner side of the tendinous expansion which 
is sent off from the extensor digitorum communis, along the pos- 
terior part of the fore-finger. 

Use. To extend the fore-finger obliquely, and to draw it in- 
wards. 

3. Prior Annularis, 

Arises, from the root of the outside of the metacarpal bone 
that sustains the ring finger. 

Inserted into the outside of the tendinous expansion of the ex- 
tensor digitorum communis which covers the ring finger. 

Use. To extend and pull the ring finger towards the thumb. 



MUSCLES ON THE BACK OF THE HAND. 339 

4. Interosseous Auricularis, 

Arises, from the root and outer side of the metacarpal bone of 
the little finger; and is 

Inserted into the outside of the tendinous expansion of the ex- 
tensor digitorum communis, which covers the posterior part of 
the little finger. 

Use. To extend and draw the little finger outwards. 

On the back of the hand three muscles of the same kind are 
to be seen, which also appear on the palm. 

Posterior Interosseous Muscles. 
1. Prior Medii, 

Arises, by two origins, from the root of the metacarpal bones 
that sustain the fore and middle fingers externally, and next each 
other: runs along the outside of the middle finger; and, being 
conspicuous on both sides of the hand, is 

Inserted into the outside of the tendinous expansion from the 
extensor digitorum communis, which covers the posterior part of 
the middle finger. 

Use. To extend and to draw the middle finger outwards. 

2. Posterior Medii, 

Arises, by two origins, from the roots of the metacarpal bones 
next each other, that sustain the middle and ring fingers. 

Inserted into the inside of the tendinous expansion from the 
extensor digitorum communis, which runs along the posterior 
part of the middle finger. 

Use. To extend and draw the middle finger inwards. 

3. Posterior Annularis, 

Arises, by two origins, from the roots of the metacarpal bones 
that sustain the ring and little fingers, next each other. 

Inserted into the inside of the tendon on the back of the ring 
finger. 



340 MUSCLES OF THE OS FEMORIS. 

Use. To draw the ring finger inward. 

The following muscle also appears on the back of the hand. 

Abductor Indicis Manus, 

Arises, from the os trapezium, and from the superior part and 
inner side of the metacarpal bone of the thumb. 

Inserted, by a short tendon, into the outer and back part of the 
first bone of the fore finger. 

Use. To bring the fore finger towards the thumb. 



MUSCLES OF THE INFERIOR EXTREMITIES. 

These may be divided into the muscles situated on the outside 
of the pelvis, on the thigh, on the leg, and on the foot. 

The muscles on the outside of the pelvis, which are called 
muscles of the thigh, 

Are composed of one layer before and three layer's behind. 

The layer before consists of five muscles : 



1. Psoas Magnus. 

2. Iliacus Internus. 



\ See p. 315, 316. 



3. Pectinalis, 

Arises, broad and fleshy, from the upper and anterior part of 
the os pubis or pectinis, immediately above the foramen thy- 
roideum. 

Inserted into the anterior and upper part of the linea aspera 
of the os femoris, a little below the trochanter minor, by a flat 
and short tendon. 

Use. To bring the thigh upwards and inwards, and to give it 
a degree of rotation outwards. 

4. Triceps Adductor Femoris, 

Under this appellation are comprehended three distinct mus- 
cles: 



MUSCLES OF THE OS F^MOR IS. 34 J 

a. Adductor Longus Femoris, 

Arises, by a strong roundish tendon, from the upper and ante- 
rior part of the os pubis, and from the symphysis pubis, on the 
inner side of the pectinalis. 

Inserted, tendinous, near the middle of the posterior part of 
the linea aspera, being continued for some way down. 

b. Adductor Brevis Femoris, 

Arises, tendinous, from the os pubis near its joining with the 
opposite os pubis, below and behind the former. 

Inserted, tendinous and fleshy, into the inner and upper part of 
the linea aspera, from a little below the trochanter minor, to the 
beginning of the insertion of the adductor longus. 

c. Adductor Magnus Femoris, 

Arises, a little lower down than the former, near the symphysis 
of the ossa pubis, tendinous and fleshy from the tuberosity of 
the os ischium ; the fibres run outwards and downwards. 

Inserted into almost the whole length of the linea aspera; 
into a ridge above the internal condyle of the os femoris ; and, 
by a roundish long tendon, into the upper part of that condyle, a 
little above which, the femoral artery takes a spiral turn towards 
the ham, passing between this muscle and the bone. 

Use of these three muscles, or triceps. To bring the thigh 
inwards and upwards, according to the different directions of 
their fibres ; and, in some degree, to roll the thigh outwards. 

5. Obturator Externus, 

Arises, fleshy, from the lower part of the os pubis, and fore- 
part of the inner crus of the ischium ; surrounds the foramen 
thyroideum ; a number of its fibres, arising from the membrane 
which fills up that foramen, are collected like rays towards a 
centre, and pass outwards around the root of the back part of 
the cervix of the os femoris. 

29* 



342 MUSCLES OF THE OS FEMORIS. 

Inserted, by a strong tendon, into the cavity at the inner and 
back part of the root of the trochanter major, adhering in its 
course to the capsular ligament of the thigh bone. 

Use. To roll the thigh bone obliquely outwards, and to pre- 
vent the capsular ligament from being pinched. 

Behind are, 

First layer, 

Gluteus Maximus, 

Arises, fleshy, from the posterior part of the spine of the os 
ilium, a little higher up than the joining of the ilium with the os 
sacrum, from the whole external side of the os sacrum, below 
the posterior spinous process of the os ilium ; from the posterior 
s*acro-ischiatic ligament, over which part of the inferior edge of 
this muscle hangs in a folded manner, and from the os coccygis. 
All the fleshy fibres run obliquely forwards, and a little down- 
wards, to form a thick broad muscle, which is divided into a 
number of strong fasciculi. The upper part of it covers almost 
the whole of the trochanter major, between which and the ten- 
don of this muscle there is a large bursa mucosa, and where it 
is inseparably joined to the broad tendon of the tensor vagina 
femoris. 

Inserted, by a strong, thick, and broad tendon, into the upper 
and outer part of the linea aspera, which is continued from the 
trochanter major, for some way downwards, as far as the origin 
of the short head of the biceps flexor cruris — and also into the 
fascia femoris. 

Use. To extend the thigh, by pulling it directly backwards, 
and a little outwards. 

Second layer, 

Gluteus Medius, 

Arises, fleshy, from the anterior superior spinous process of the 
os ilium, and from all the outer edge of the spine of the ilium ; 
except its posterior part, where it arises from the dorsum of that 
bone. 

Inserted, by a broad tendon, into the outer and upper margin 
of the trochanter major. 



MUSCLES OF THE OS FEMORIS. 343 

Use. To draw the thigh bone outwards, and a little back- 
wards; to roll the thigh bone outwards, especially when it is 
bended. 

N. B. The anterior and upper part of this muscle is covered 
by a tendinous membrane, from which a number of its fleshy 
fibres arise, and which joins with the broad tendons of the glu- 
teus maximus, tensor vagina3 femoris, and latissimus dorsi. 

Third layer consists of four muscles. 

1. Gluteus Minimus, 

Arises, fleshy, from a ridge that is continued from the superior 
anterior spinous process of the os ilium, and from the middle of 
the dorsum of that bone, as far back as its great niche. 

Inserted, by a strong tendon, into the fore and upper part of 
the trochanter major. 

Use. To assist the former in pulling the thigh outwards and 
backwards, and in rolling it. 

2. Pyriformis, 

Arises, within the pelvis, by three tendinous and fleshy ori- 
gins, from the second, third, and fourth pieces of the os sacrum; 
from thence growing gradually narrower, it passes out of the 
pelvis along with the posterior crural nerve, below the niche in 
the posterior part of the os ilium, where it receives a few fleshy 
fibres. 

Inserted, by a roundish tendon, into the upper part of the ca- 
vity, at the inner side of the root of the trochanter major. 

Use. To move the thigh a little upwards, and roll it outwards. 

3. Gemini, 

Arises, by two distinct origins ; the superior from the spinous 
process, and the inferior from the tuberosity of the os ischium ; 
also, from the posterior sacro-ischiatic ligament. They are both 
united by a tendinous fleshy membrane, and form a purse for 
the tendon of the obturator internus muscle, which was for- 
merly described. 

Inserted, tendinous and fleshy, into the cavity at the inner side 



344 MUSCLES OF THE THIGH. 

of the root of the trochanter major, on each side of the tendon 
of the obturator internus, to which they firmly adhere. 

Use. To roll the thigh outwards, and to preserve the tendon 
of the obturator internus from being hurt by the hardness of that 
part of the os ischium over which it passes ; also, to hinder it 
from starting out of its place, while the muscle is in action. 

4. Quadratics Femoris, 

Arises, tendinous and fleshy, from the outside of the tuberosity 
of the os ischium ; and, running transversely, is 

Inserted, fleshy, into a rough ridge, continued from the root of 
the large trochanter to the root of the small one. 

Use. To roll the thigh outwards. 

Muscles situated on the Thigh. 

These are called muscles of the leg ; and consist of one, on the 
outside ; two, on the inside ; four, before ; and four, behind. 

Previous to the description of the muscles that are situated on 
the thigh and leg, it is necessary to take notice of a broad ten- 
dinous fascia or sheath, {aponeurosis of the lower extremities,) 
which is sent off from the back and from the tendon of the 
glutei and adjacent muscles. 

It is a strong thick membrane on the outside of the thigh and 
leg ; but, towards the inside of both, it gradually turns thinner, 
and has rather the appearance of cellular substance than a ten- 
dinous membrane. A little below the trochanter major, it is 
firmly fixed to the linea aspera; and, farther down, to that part 
of the head of the tibia that is next the fibula ; where it sends off 
the tendinous expansion along the outside of the leg. 

It serves to strengthen the action of the muscles, by keeping 
them firm in their proper places while in action, particularly the 
tendons that pass over the joints where this membrane is thickest, 
and it gives origin to a number of the fleshy fibres of the mus- 
cles. 

On the outside is, 



MUSCLES OP THE THIGH. 345 

Tensor Vagince Femoris, 

Arises, by a narrow, tendinous, and fleshy beginning, from the 
external part of the anterior superior spinous process of the os 
ilium. 

Inserted, a little below the trochanter major, into the inner 
side of the membranous fascia which covers the outside of the 
thigh. 

Use. To stretch the membranous fascia, to assist in the ad- 
duction of the thigh, and somewhat in its rotation inwards. 

On the inside are, 

1. Sartorius, 

Arises, tendinous from the anterior superior spinous process of 
the os ilium, soon grows fleshy, runs down for some space upon 
the rectus, and going obliquely inwards, it passes over the vastus 
internus, and, about the middle of the os femoris, over part of 
the triceps; it runs down farther between the tendon of the ad- 
ductor magnus and that of the gracilis muscles. 

Inserted, by a broad and thin tendon, into the inner side of the 
tibia, near the inferior part of its tubercle. 

Use. To bend the leg obliquely inwards, or to bring one leg 
across the other. 

2. Gracilis, 

Arises, by a thin tendon, from the os pubis, near the symphysis 
of these two bones, soon grows fleshy, and, descending by the in- 
side of the thigh, is 

Inserted, tendinous, into the tibia under the sartorius. 

Use. To assist the sartorius. 

Before are, 

1. Rectus, 

Arises, fleshy, from the inferior anterior spinous process of the 
os ilium, and tendinous from the dorsum of the ilium, a little 
above the acetabulum ; runs down over the anterior part of the 



346 MUSCLES OF THE THIGH. 

cervix of the os femovis; the fibres not being straight, but run- 
ning down like the plumage of a feather obliquely outwards and 
inwards, from a tendon in the middle. 

Inserted, tendinous, into the upper part of the patella, from 
which a thin tendon runs down, on the forepart of this bone, to 
terminate in a thick strong ligament, which is sent off from the 
inferior part of the patella, and inserted into the tubercle of the 
tibia. 

Use. To extend the leg, and, in a powerful manner, by the 
intervention of the patella, like a pulley. 

2. Vastus Externus, 

Arises, broad, tendinous and fleshy, from the root of the tro- 
chanter major, and upper part of the linea aspera ; its origin be- 
ing continued from near the insertion of the gluteus minimus, 
the whole length of the linea aspera, by fleshy fibres which run 
obliquely forwards to a middle tendon, where they terminate. 

Inserted into a large share of the upper part of the patella; 
and part of it ends in an aponeurosis, which is continued down 
to the leg, and in its passage is firmly fixed to the head of the 
tibia. 

Use. To extend the leg. 

3. Vastus Internus, 

Arises, tendinous and fleshy, from between the forepart of the 
os femoris and root of the trochanter minor, and from almost all 
the inside of the linea aspera, by fibres running obliquely for- 
wards and downwards. 

Inserted, tendinous, into the upper and inside of the patella, 
continuing fleshy lower than the vastus externus. Part of it 
likewise ends in an aponeurosis continued down to the leg, and 
fixed in its passage to the upper part of the tibia. 

Use. To extend the leg. 

4. Cruralis, 
Arises, fleshy, from between the two trochanters of the os 



MUSCLES OF THE THIGH. 347 

femoris, but nearer the lesser trochanter, and firmly adhering to 
most of the forepart of the os femoris, and connected to both 
vasti muscles. 

Inserted, tendinous, into the upper part of the patella, behind 
the rectus. 

Use. To assist in the extension of the leg. 

N. B. These four muscles, before, being inserted into the pa- 
tella, have the same effect upon the leg as if they were imme- 
diately inserted into it by means of the strong tendon, or rather 
ligament which is sent off from the inferior part of the patella to 
the tibia. 

Behind are, 

1. Semitendinosus, 

Arises, tendinous and fleshy, in common with the long head of 
the biceps, from the posterior part of the tuberosity of the os 
ischium ; and sending down a long roundish tendon, which ends 
flat, is 

Inserted into the inside of the ridge of the tibia, a little below 
its tubercle. 

Use. To bend the leg backwards and a little inwards. 

2. Semimembranosus, 

Arises, tendinous, from the upper and posterior part of the 
tuberosity of the os ischium ; sends down a broad flat tendon, 
which ends in a fleshy belly, and, in its descent, runs at first on 
the forepart of the biceps, and lower, between it and the semi- 
tendinosus. 

Inserted, tendinous, into the inner and back part of the head 
of the tibia. 

Use. To bend the leg, and bring it directly backward. 

JV. B. The two last form what is called the inner hamstring. 

3. Biceps Flexor Cruris, 

Arises by two distinct heads. The first, called longus, arises, 
in common with the semitendinosus, from the upper and poste- 
rior part of the tuberosity of the os ischium. The second, 



348 MUSCLES ON THE FRONT OF THE LEG. 

called brevis, arises from the linea aspera, a little below the ter- 
mination of the gluteus maximus, by a fleshy acute beginning, 
which soon grows broader as it descends to join with the first 
head, a little above the external condyle of the os femoris. 

Inserted, by a strong tendon, into the upper part of the head 
of the fibula. 

Use. To bend the leg. 

N. B. This muscle forms what is called the outer hamstring; 
and between it and the inner, the nervus popliteus, the arteria 
and vena poplitea, are situated. 

4. Popliteus, 

Arises, by a round tendon, from the lower and back part of 
the external condyle of the os femoris, then runs over the liga- 
ment that involves the joint ; firmly adhering to it, and part of 
the semilunar cartilage. As it runs over the joint, it becomes 
fleshy, and the fibres run obliquely inwards, being covered with 
a thin tendinous membrane. 

Inserted, broad, thin and fleshy, into a ridge at the upper and 
internal edge of the tibia, a little below its head. 

Use. To assist in bending the leg, and to prevent the capsular 
ligament from being pinched. After the leg is bent, this muscle 
serves to roll it inwards. 

Muscles situated on the Leg. 

These muscles may be arranged in the two general classes of flexors and 
extensors of the foot, and flexors and extensors of the toes ; but several of 
them, viz. the tibialis and the peronei, produce effects which are different 
from flexion or extension. For the accommodation of the student of ana- 
tomy, they may be studied in the order of their position as they lie on the 
front, on the outside, and on the back of the leg. 

Muscles on the Front of the Leg. 

1. Tibialis Anticus, 

Arises, tendinous and fleshy, from the middle of that process 
of the tibia, to which the fibula is connected above; then it 
runs down fleshy on the outside of the tibia ; from which, and 



MUSCLES ON THE LEG. 



349 



the upper part of the interosseous ligament, it receives a number 
of distinct fleshy fibres ; near the extremity of the tibia, it sends 
off a strong round tendon, which passes under part of the liga- 
mentutn tarsi annulare near the malleolus internus. 

Inserted, tendinous, into the inside of the os cuneiforme inter- 
num, and posterior end of the metatarsal bone that sustains the 
great toe. 

Use. To bend the foot, by drawing it upwards, and, at the 
same time, to turn the toes inwards. 

Extensor Proprius Pollicis Pedis, 

Arises, by an acute, tendinous, and fleshy beginning, some 
way below the head and anterior part of the fibula, along which 
it runs to near its lower extremity, connected to it by a number 
of fleshy fibres, which descend obliquely towards a tendon. 

Inserted, tendinous, into the posterior part of the first and last 
joint of the great toe. 

Use. To extend the great toe. 

3. Extensor Longus Digitorum Pedis, 

Arises, tendinous and fleshy, from the upper and outer part of 
the head of the tibia, and from the head of the fibula where it 
joins with the tibia, and from the interosseous ligament ; also 
from the tendinous fascia, which covers the upper and outside 
of the leg by a number of fleshy fibres ; and tendinous and fleshy 
from the anterior spine of the fibula, almost its whole length, 
where it is inseparable from the peroneus tertius. It splits into 
four round tendons, under the ligamentum tarsi annulare. 

Inserted, by a flat tendon, into the root of the first joint of 
each of the four small toes ; and is expanded over the upper side 
of the toes, as far as the root of the last joint. 

Use. To extend all the joints of the four small toes. 

N. B. A portion of this muscle, which is called 

4. Peroneus Tertius, 

Arises, from the middle of the fibula, continues down to near 
vol. i. 30 



350 MUSCLES ON THE LEG. 

its inferior extremity, and sends its fleshy fibres forwards to a 
tendon, which passes under the annular ligament, and is 

Inserted, into the root of the metatarsal bone that sustains the 
little toe. 

Use. To assist in bending the foot. 

Muscles on the outside of the Leg. 

1. Peroneus Longus, 

Arises, tendinous and fleshy, from the forepart of the head of 
the peroneus, or fibula, the fibres running straight down; also from 
the upper and external part of the fibula, where it begins to rise 
into a round edge ; as, also, from the hollow between that and 
its anterior edge, as far down as to reach within a hand's breadth 
of the ankle, by a number of fleshy fibres, which run outwards 
towards a tendon, that subsequently becomes long and round, 
and passes through a channel at the outer ankle, in the back 
part of the inferior extremity of the fibula ; then being reflected 
to the sinuosity of the os calcis, it runs along a groove in the 
os cuboides, above the muscles in the sole of the foot. 

Inserted, tendinous, into the outside of the root of the meta- 
tarsal bone that sustains the great toe, and by some tendinous 
fibres into the os cuneiforme internum. 

Use. To turn the foot outwards, and to extend it a little. 

2. Peroneus Brevis, 

Arises, by an acute fleshy beginning, from above the middle 
of the external part of the fibula ; from the outer side of the an- 
terior spine of this bone ; as also from its round edge externally, 
the fibres running obliquely outwards towards a tendon on its 
external side : it sends off a round tendon which passes through 
the groove at the outer ankle, being there included under the 
same ligament with that of the preceding muscle ; and a little 
farther, it runs through a particular one of its own. 

Inserted, tendinous, into the root and external part of the 
metatarsal bone that sustains the little toe. 

Use. To assist the former in pulling the foot outwards, and 
extending it a little. 



MUSCLES ON THE LEG. 35 1 

Muscles on the back of the Leg. 

1. Gastrocnemius Externus, seu Gemellus, 

Arises, by two distinct heads. The first head arises from the 
upper and back part of the internal condyle of the os femoris, 
and from that bone, a little above its condyle, by two distinct 
tendinous origins. .The second head arises tendinous from the 
upper and back part of the external condyle of the os femoris. 
A little below the joint, their fleshy bellies unite in a middle ten- 
don ; and, below the middle of the tibia, it sends off a broad thin 
tendon, which joins a little above the extremity of the tibia with 
the tendon of the following. 

2. Soleus, seu Gastrocnemius Internus, 
Arises by two origins. The first is from the upper and back 
part of the head of the fibula, continuing to receive many of its 
fleshy fibres from the posterior part of that bone for some space 
below its head. The other origin begins from the posterior and 
upper part of the middle of the tibia ; and runs inwards along 
the inferior edge of the popliteus towards the inner part of the 
tibia, from which it receives fleshy fibres for some way down. 
The flesh of this muscle, covered by the tendon of the gemellus, 
runs down nearly as far as the extremity of the tibia ; a little 
above which the tendons of both gastrocnemii unite, and form a 
strong round chord, which is called tendo-achillis. 

Inserted into the upper and posterior part of the os calcis, by 
the projection of which the tendo-achillis is placed at a considera- 
ble distance from the tibia. 

Use. To extend the foot, by bringing it backwards and down- 
wards. 

3. Plantaris, 

Arises, thin and fleshy, from the upper and back part of the 
root of the external condyle of the os femoris, near the interior 
extremity of that bone, adhering to the ligament that involves 
the joint in its descent. It passes along the second origin of the 
soleus and under the gemellus, where it sends off a long, slender, 



352 MUSCLES ON THE LEG. 

thin tendon, which comes from between the great extensors, 
where they join tendons ; then runs down by the inside of the 
tendo-achillis. 

Inserted, into the inside of the posterior part of the os calcis, 
below the tendo-achillis. 

Use. To assist the former, and to pull the capsular ligament 
of the knee from between the bones. It seems likewise to as- 
sist in rolling the foot forwards. 

4. Flexor Longus Digitorum Pedis, Profundi s, Perforans, 

Arises by an acute tendon, which soon becomes fleshy from 
the back part of the tibia, some way below its head, near the 
entry of the medullary artery ; which beginning, is continued 
down the inner edge of this bone by short fleshy fibres, ending 
in its tendon ; also by tendinous and fleshy fibres, from the outer 
edge of the tibia, and between this double order of fibres, the 
tibialis posticus muscle lies enclosed. Having passed under two 
annular ligaments, it then passes through a sinuosity at the inside 
of the os calcis; and about the middle of the sole of the foot, 
divides into four tendons, which passes through the slits of the 
perforatus ; and just before its division it receives a considera- 
ble tendon from that of the flexor pollicis longus. 

Inserted into the extremity of the last joint of the four lesser 
toes. 

Use. To bend the last joint of the toes. 

5. Tibialis Posticus, 

Arises, by a narrow fleshy beginning, from the fore and upper 
part of the tibia, just under the process which joins it to the 
fibula ; then passing through a perforation in the upper part of 
the interosseous ligament, it continues its origin from the back 
part of the fibula next the tibia, and from near one half of the 
upper part of the last named bone ; as also, from the interosse- 
ous ligament, the fibres running towards a middle tendon, which 
sends off a round one that passes in a groove behind the malleo- 
lus internus. 

Inserted, tendinous, into the upper and inner part of the os 



MUSCLES ON THE SOLE OF THE FOOT. 353 

naviculare, being farther continued to the os cuneiforme inter- 
num and medium; besides it gives some tendinous filaments to 
the os calcis, os cuboides, and to the root of the metatarsal bone 
that sustains the middle toe. 

Use. To extend the foot, and to turn the toes inwards. 

6. Flexor Longus Pollicis Pedis, 

Arises, by an acute, tendinous, and fleshy beginning, from the 
posterior part of the fibula, some way below its head, being con- 
tinued down the same bone, almost to its inferior extremity, by 
a double order of oblique fleshy fibres ; its tendon passes under 
an annular ligament at the inner ankle. 

Inserted into the last joint of the great toe, and, generally, 
sends a small tendon to the os calcis. 

Use. To bend the last joint of this toe. 

On the upper surface of the foot there is one muscle, viz. 

Extensor Brevis Digitorum Pedis, 

Arises, fleshy and tendinous, from the fore and upper part of 
the os calcis ; and soon forms a fleshy belly, divisible into four 
portions, which send oft* an equal number of tendons that pass 
over the upper part of the foot, under the tendons of the former. 

Inserted, by four slender tendons, into the tendinous expansion 
from the extensor longus which covers the small toes, except the 
little one; also into the tendinous expansion from the extensor 
pollicis, that covers the upper part of the great toe. 

Use. To extend the toes. 

Muscles on the Sole of the Foot. 

On the sole of the foot there is a strong tendinous membrane called Apo- 
neurosis Plantaris, which originates from the tuberosity of the os calcis, 
and proceeds forward to the toes, increasing gradually in breadth. 

It is divided into three portions. That in the middle is the largest; it pro- 
tects and covers the short flexor muscles, and the tendons in the middle 
of the foot. That on the outside, which covers the adductor and flexor of 
the little toe, is next in size. The internal portion, which covers the ad- 
ductor of the great toe, is the smallest. 

30 * 



354 MUSCLES 0\ THE SOLE OF THE FOOT. 

The edges of these portions dip down so as to separate the muscles they 
cover from each other. They are divided into five processes, correspond- 
ing with the heads of the metatarsal bones ; each of these portions is di- 
vided into two bands, which are inserted into each side of the head of 
each metatarsal bone, and the tendons, nerves, and arteries pass between 
them. 

Immediately under the middle portion of this aponeurosis are the common 
short flexors of the toes, viz. 

1. Flexor Brevis Digitorum Pedis Sublimis Perforatus, 

Arises, by a narrow fleshy beginning, from the inferior and 
posterior part of the protuberance of the os calcis, between the 
adductors of the great and little toes, soon forms a thick fleshy 
belly, which sends off four tendons that split for the passage of 
the flexor longus. 

Inserted into the second phalanx of the four lesser toes. The 
tendon of the little toe is often wanting. 

Use. To bend the second joint of the toes. 

2. Flexor Digitorum Accessorius, seu, Massa Cornea Jacobii 
Sylvii, 

Arises, by a thin fleshy origin, from most part of the sinuosity 
at the inside of the os calcis, which is continued forwards, for 
some space on the same bone ; also, by a thin tendinous begin- 
ning, from before the tuberosity of the os calcis, externally, and, 
soon becoming all fleshy, is 

Inserted into the tendon of the flexor longus, just at its division 
into four tendons. 

Use. To assist the flexor longus. 

3. Lumbricales Pedis, 

Arises, by four tendinous and fleshy beginnings, from the ten- 
don of the flexor profundus, just before its division, near the in- 
sertion of the massa carnea. 

Inserted, by four slender tendons, into the inside of the first 
joint of the four lesser toes, and are lost in the tendinous expan- 
sion that is sent from the extensors to cover the upper part of 
the toes. 



MUSCLES ON THE SOLE OF THE FOOT. 355 

Use. To increase the flexion of the toes, and to draw them 
inwards. 

On the inside of the foot, and under the common flexors, are 
the muscles which are considered as exclusively appropriated to 
the great toe, viz. 

1. Abductor Pollicis Pedis, 

Arises from the internal side of the tuberosity of the os calcis, 
and from a ligament which extends from this tuberosity to the 
sheath of the tendon of the tibialis posticus muscle, and also 
from the internal and inferior side of the os naviculare and 
cuneiforme internum. It likewise arises from that portion of the 
aponeurosis plantaris, which separates it from the short flexor of 
the toes, and many of its fibres appear to be connected with the 
ligaments which pass from the posterior to the anterior bones of 
the foot : as it passes under the cuneiform bone, a portion of its 
lower surface is tendinous. 

It is inseparably connected to the flexor of the great toe, and 
is inserted into the internal sesamoid bone, and the inferior and 
internal part of the root of the first bones of the great toe. 

This muscle not only separates the great toe from the other 
toes, but it must increase the curvature, or arched form of the 
foot. 

2. Flexor Brevis Pollicis Pedis, 

Arises, tendinous, from the under and forepart of the os calcis, 
where it joins with the os cuboides, from the os cuneiforme ex- 
ternum, and is inseparably united with the abductor and adduc- 
tor pollicis. 

Inserted into the internal and external sesamoid bones, along 
with the abductor and adductor pollicis, and into the root of the 
first joint of the great toe. 

Use. To bend the first joint. 

3. Adductor Pollicis Pedis, 
Arises, by a long thin tendon, from the os calcis, from the os 
cuboides, from the os cuneiforme externum, and from the root of 
the metatarsal bone of the second toe. 



356 MUSCLES ON THE SOLE OF THE FOOT. 

Inserted into the external os sesamoideum, and root of the 
metatarsal bone of the great toe. 

Use. To bring this toe nearer the rest. 

Near the outer edge of the foot, under the second portion of 
the aponeurosis plantaris, are the muscles peculiar to the little 
toe, viz. 

1. Abductor Minimi Digiii Pedis, 

Arises, tendinous and fleshy, from the semicircular edge of a 
cavity on the inferior part of the protuberance of the os calcis, 
and from the root of the metatarsal bone of the little toe. 

Inserted into the root of the first joint of the little toe exter- 
nally. 

Use. To draw the little toe outwards from the rest, and assist 
in preserving the arched form of the foot. 

2. Flexor Brevis Minimi Digiti Pedis, 

Arises, tendinous, from the os cuboides, near the sulcus or fur- 
row for lodging the tendon of the peroneus longus; fleshy from 
the outside of the metatarsal bone that sustains the little toe, be- 
low its protuberant part. 

Inserted, into the anterior extremity of the metatarsal bone, 
and root of the first joint of this toe. 

Use. To bend this toe. 

Between the metatarsal bones are four external and three internal inter- 
ossei : and one muscle which is common to all the metatarsal bones. 

Interossei Pedis Externi, Bicipites. 

1. Abductor Indicis Pedis, 

Arises, tendinous and fleshy, by two origins, from the root of 
the inside of the metatarsal bone of the fore toe, from the outside 
of the root of the metatarsal bone of the great toe, and from the 
os cuneiforme internum. 

Inserted, tendinous, into the inside of the root of the first joint 
of the fore toe. 



INTEROSSEOUS MUSCLES. 357 

Use. To pull the fore toe inwards from the rest of the small 
toes. 

2. Adductor Indicis Pedis, 

Arises, tendinous and fleshy, from the roots of the metatarsal 
bones of the fore and second toe. 

Inserted, tendinous, into the outside of the root of the first joint 
of the fore toe. 

Use. To pull the fore toe outwards towards the rest. 

3. Adductor Medii Digiti Pedis, 

Arises, tendinous and fleshy, from the roots of the metatarsal 
bones of the second and third toes. 

Inserted, tendinous, into the outside of the root of the first joint 
of the second toe. 

Use. To pull the second toe outwards. 

4. Adductor Tertii Digiti Pedis, 

Arises, tendinous and fleshy, from the roots of the metatarsal 
bones of the third and little toe. 

Inserted, tendinous into the outside of the root of the first joint 
of the third toe. 

Use. To pull the third toe outwards. 

Interossei Pedis Interni, 

1. Abductor Medii Digiti Pedis, 

Arises, tendinous and fleshy, from the inside of the root of the 
metatarsal bone of the middle toe internally. 

Inserted, tendinous, into the inside of the root of the first joint 
of the middle toe. 

Use. To pull the middle toe inwards. 

2. Abductor Tertii Digiti Pedis, 

Arises, tendinous and fleshy, from the inside and inferior part 
of the root of the metatarsal bone of the third toe. 



358 INTEROSSEOUS MUSCLES. 

Inserted, tendinous, into the inside of the root of the first joint 
of the third toe. 

Use. To pull the third toe inwards. 

3. Abductor Minimi Digiti Pedis, 

Arises, tendinous and fleshy, from the inside of the root of the 
metatarsal bone of the* little toe. 

Inserted, tendinous, into the inside of the root of the first joint 
of the little toe. 

Use. To pull the little toe inwards. 

The common muscle, 

Transversalis Pedis, 

Arises, tendinous, from the under part of the anterior extremity 
of the metatarsal bone of the great toe, and from the internal os 
sesamoideum of the first joint, adhering to the adductor pollicis. 

Inserted, tendinous, into the under and outer part of the anterior 
extremity of the metatarsal bone of the little toe, and ligament 
of the next toe. 

Use, to contract the foot, by bringing the great toe and the two 
outermost toes nearer each other. 



MOTIONS OF THE SKELETON. 359 



CHAPTER JX. 

OBSERVATIONS ON THE MOTIONS OF THE SKELETON. 

The falling down of the body during life, when muscular ac- 
tion is suspended, as well as the examination of the artificial 
skeleton, evince that this machine is not constructed to preserve 
the erect position of itself; but that, when unsupported, it bends 
at the joints, and invariably falls forward. 

It is retained in the erect position by the action of muscles : 
and that the muscles should produce this effect, it is necessary 
that they should have a fixed basis to act from. 

This basis is the feet, and they are fixed to the ground by the 
weight of the body. 

To keep the body from falling, it is necessary that the centre 
of gravity should be immediately over the centre of the com- 
mon basis. 

All our movements, both in walking, standing, and rising from 
our seats, are regulated by this principle ; and whenever we 
move our body, so that the centre of gravity is changed, we 
must change the position of the feet, that the centre of the basis 
may be directly under it. 

If this proposition were not almost self-evident, it might be 
illustrated by several very easy experiments. 

If a person stand against a wall with his heels and the back 
parts of his legs and thighs in contact with it, and, in this situa- 
tion, attempts to stoop forward, he will fall upon his face; there 
is no power in his muscles, or in any other part of the body, 
when thus circumstanced, to prevent it; but a small movement 
forward of one foot, will enable him to stoop with ease by alter- 
ing the basis of the body. 

When we sit in such a position that we cannot bring the cen- 



ggO ADJUSTMENT OF THE CENTRE OF GRAVITY. 

tre of gravity over the feet, the lower limbs are divested of all 
power of elevating the body : this is always the case when we 
sit with the thighs and legs at right angles with each other. 
Bend the knees to an acute angle, so that the feet are placed un- 
der the body, and we rise with ease. 

When we wish to stoop forward without advancing one of 
our feet, we acquire the power in a small degree, by placing our 
hands behind us, to preserve the equilibrium. 

Some old persons, whose spines curve forwards in conse- 
quence of age, bend their lower limbs, so that the pelvis may be 
projected backwards beyond the centre of the base of the body, 
and form a counterpoise to the upper part of the trunk. 

Bending the knees alone, without projecting the pelvis back- 
wards, will not produce this effect ; for a person who stands 
with his back to a wall will bend his knees without obtaining 
this advantage, while the heels and back part of the pelvis are in 
contact with the wall. 

When we stand with the toes pointing directly forwards, the 
base of the body is a square ; of which the feet are two of the 
sides. As the positions of the feet are changed, the figure of the 
base and its centre necessarily change also. When the feet are 
placed one immediately before the other, the centre is between 
the toes of the one and the heel of the other. When the posi- 
tion of the feet is such, that the toes point directly outwards, and 
the heels are opposite to each other, the centre of the base is be- 
tween the heels. 

In these cases, when the situation of the centre of the base is 
changed, we immediately change the centre of gravity. Thus, 
as we turn the toes outwards, the centre of the base moves 
backwards, we, therefore, immediately make the body more 
erect ; and by that means keep the centre of gravity over the 
centre of the base. 

We move the centre of gravity laterally, as well as back- 
wards and forwards, in conformity to this principle. 

Thus, when we raise one foot from the ground, the body in- 
clines so much in the opposite direction, that the centre of 



ADJUSTMENT OF THE CENTRE OF GRAVITY. 361 

gravity is directly over the other. If the spine is diseased in 
one spot, and assumes a lateral curvature, placing the centre of 
o-ravity on one side of the natural centre of the base ; another 
curve is formed by muscular action, in a sound part of the 
spine, to counteract the first, and keep the centre of gravity in 
its natural position. 

The perception of a tendency to fall, when the centre of gra- 
vity is in a wrong situation, first induces us to make efforts to 
resist this tendency ; we learn by experience what these efforts 
ought to be : and by habit we at length make them without con- 
sciousness. 

As the natural tendency of the skeleton, when we stand, is to 
bend at the articulations, and, therefore, to fall forwards ; the 
muscles which have the principal effort in keeping the body 
erect, must be the extensors. 

Thus, the muscles on the back of the leg, and particularly the 
soleus, keep the tibia erect : while the muscles on the front of 
the thigh, the vasti and crureus, produce the same effect upon 
the os femoris : the bones being kept steady by the occasional 
counteraction of the antagonist muscles. 

The whole lower limb is thus made erect by an exertion 
which begins at the foot, while the foot is fixed to the ground by 
the weight and pressure of the body above it. 

The trunk of the body has a strong tendency to bend forward 
at the articulations of the thigh bones and the ossa innominata. 
This tendency is resisted by the muscles which lie on the back 
part of the ossa femoris, and extend the trunk on those bones 
viz. the glutei maximi. 

The muscles which arise from the tuberosity of the ischium, 
and are inserted into the leg, the semitendinosus, semimembra- 
nosus, and the long head of the biceps flexor cruris, have also 
this effect. 

The flexure of the thoracic and lumbar portions of the spine is 
counteracted by the sacro-lumbalis, and longissimus dorsi, which 
act from the sacrum and back parts of the pelvis. The yellow 
ligaments, which are elastic, must also co-operate to this effect: 

vol. i. 31 



362 MUSCLES WHICH KEEP THE BODY ERECT. 

so that with regard to the spine, there is an additional agent dis- 
tinct from the muscular power. 

Indeed, respecting the vertebral articulations in general, it 
may be observed, that the connexion of the bodies of the verte- 
brae, by the intervertebral cartilaginous matter, and of the plates 
behind, by the elastic ligament, renders these articulations per- 
fectly anomalous; and very different in their principles from the 
articulations in general. 

In no part of the skeleton is this tendency to bend forward 
more strongly perceived than in the head. When we are 
awake, and the muscles in a healthy situation, it is effectually 
restrained, and the head kept erect, by the splenius and corn- 
plexus, and other muscles, which act from the spine below, upon 
the back part of the head and the vertebras of the neck. 

When we stand on one foot, some very different muscles are 
called into action ; the tendency of the body is to fall sideways, 
towards the foot which is raised from the ground. To counter- 
act this tendency the two larger peronei muscles, which are 
situated on the outside of the leg, act from the foot, to keep the 
leg erect. The vastus externus acts upon the same principle 
from the leg upon the os femoris. The gluteus medius and mi- 
nimus, and the muscle of the fascia lata, act from the os femoris 
upon the pelvis and trunk ; while the quadratus lumborum, and 
those abdominal muscles which draw the spine to that side, con- 
tinue the operation: and so do likewise the muscles which act 
on the same side of the neck and head. 

In rising from a seat, the tibialis anticus acts very powerfully, 
to keep the tibia erect, and prevent it from inclining backwards. 
The two vasti, and the crurseus, raise up the os femoris, while 
the gluteus maximus, the semitendinosus, and semimembranosus, 
and the long head of the biceps, extend the trunk of the body. 

There are several modes of walking, which are different from 
each other, in a small degree. 

We may walk, for example, with the knee of the hind limb 
straight or bent, as we bring it forward. This circumstance is 
merely a matter of accommodation. But there are two essential 



MUSCLES EMPLOYED IN RISING FROM A SEAT. o fi o 

processes in walking, viz. 1. Projecting one foot forward, and 
placing it on the ground while thus projected , and 2. Moving 
the body over that foot. 

The mode of projecting the foot requires no explanation ; but 
the manner of bringing it to the ground, when thus advanced 
ought to be noticed. 

If, after standing with both feet on the same line, we move 
one foot forwards, suppose the right foot, it cannot be applied 
flat to the ground, unless we either incline the body ard or 

move the pelvis on the left thigh, so that the right aid ay pre- 
sent obliquely forward ; or lower the right side of the pelvis, so 
that it may be nearer the ground. 

When we incline the body forward, and thus bring the right 
foot to the ground, we perform the second essential process in 
walking, along with the first: for we move the body over the 
fore foot. The muscles on the front part of the hind leg, and 
particularly the tibialis anticus, seem to produce this effect, by 
bending, or inclining forward, the tibia on the foot. 

When the foot is brought to the ground by a rotation of the 
pelvis, it is likewise the tibialis anticus, and the muscles on the 
front of the hind leg, that move the body over it, or that begin 
the motion. 

The gastrocnemius and soleus, and the flexors of the toes, par- 
ticularly that of the great toe, occasionally co-operate with great 
effect. By raising the heel, and thus lengthening the hind limb, 
they push the body forward, and continue its motion in that di- 
rection after the effect of the tibialis anticus ceases. The length 
of the step appears, therefore, to require this elevation of the heel, 
and depression of the toes ; but it should be observed, that when 
we take long steps, we also turn the pelvis partly round, pre- 
senting the side obliquely forward ; and in this manner increase 
the anterior projection of the front leg. 

Although the action of the gastrocnemius, &c. seems neces- 
sary to walking with long steps, we can walk without their ope- 
ration. This is proved incontestably by the act of walking on 
the heel: when the gastrocnemii and the flexors are so far from 



364 MOTIONS NECESSARY IN WALKING. 

acting, that they are in a state of extension. In this operation, 
the principal effort seems to be made by the tibialis anticus, and 
the muscles on the front of the leg ; and the extensor muscles on 
the front of the thigh. 

Notwithstanding these facts, the action of the gastrocnemius 
and soleus is essential whenever we raise the heel from the 
ground, while the weight of the body presses on the front part of 
the foot ; and it then acts with a force which equals, if it does 
not exceed, the weight of the body. 

Jumping, at the first view of it, appears an extraordinary ope- 
ration; but if a man who lies on the ground, with his feet 
against a wall, makes a muscular exertion, such as is necessary 
for jumping, the nature of the operation is very intelligible. It 
is a sudden extension of the feet and knees, and sometimes of the 
trunk of the body. The stroke is made against the wall ; but as 
that does not yield, the whole motion is impressed upon the 
body; which is projected from the wall horizontally in the 
same way that in jumping, it is projected from the ground ver- 
tically. 



365 



EXPLANATION OP' PLATES VI. AND VII. 



Plate VI. 



Fig. 1. The Muscles immediately under the common teguments on the an- 
terior part of the body are represented on the right side ; and on the left 
side the Muscles are seen which come in view when the exterior ones 
are taken away. 

A, The frontal muscle. B, The tendinous aponeurosis which joins it to 
the occipital ; hence both are named occipito-frontalis. C, Attollens aurem. 
D, The ear. E, Anterior auris. F F, Orbicularis palpebrarum. G, Le- 
vator labii superioris alseque nasi. H, Levator anguli oris. I, Zygomati- 
cs minor. K, Zygomaticus major. L, Masseter. M, Orbicularis oris. 
N, Depressor labii inferioris. O, Depressor anguli oris. P, Buccinator. 
Q.Q, Platysma myoides. RR, Sterno-cleido-mastoideus. S, Part of the 
trapezius. T, Part of the scaleni. 

Superior Extremity. — U, Deltoides. V, Pectoralis major. W, Part 
of the latissimus dorsi. X X, Biceps flexor cubiti. Y Y, Part of the tri- 
ceps extensor. Z Z, The beginning of the tendinous aponeurosis, (from the 
biceps,) which is spread over the muscles of the forearm, a a, Its strong 
tendon inserted into the tubercle of the radius, bb, Part of the brachialis 
internus. c, Pronator radii teres, d, Flexor carpi radialis. e, Part of the 
flexor carpi ulnaris. f, Palmaris longus. g, Aponeurosis pal maris. 3, pal- 
maris brevis. 1, Ligamentum carpi annulare. 2 2, Abductor minimi digi- 
ti. h, Supinator radii longus. i, The tendons of the thumb, k, Abductor 
pollicis. 1, Flexor pollicis longus. m m, The tendons of the flexor subli- 
mis perforatus, profundus perforans, and lumbricales. The sheaths are en- 
tire in the right hand, — in the left cut open to show the tendons of the flexor 
profundus perforating the sublimis. 

Muscles — not referred to — in the left superior extremity, n, Pectoralis 
minor, seu serratus anticus minor, o, The two heads of (x x) the biceps, 
p, Coraco-brachialis. q q, The long head of the triceps extensor cubiti. r r, 
Teres major, ss, Subscapularis. tt, Extensores radialis. u, Supinator 
brevis. v, The cut extremity of the pronator teres, w, Flexor sublimis 
perforatus. x, Part of the flexor profundus, y, Flexor pollicis longus. z, 
Part of the flexor pollicis brevis. 4, Abductor minimi digiti. 5, The four 
lumbricales. 

Trunk. — 6. Serrated extremities of the serratus anticus major. 7 7, Ob- 
liquus externus abdominis. 88, The linea alba. 9, The umbilicus. 10, 
Pyramidalis. 11 11, The spermatic cord. On the left side it is covered by 

31 * 



366 EXPLANATION OF THE PLATES OF THE MUSCLES. 

the cremastet. 12 12, Rectus abdominis. 13, Obliquus interims. 14 14, 
&c. Intercostal muscles. 

Inferior Extremities. — a a, The gracilis, b b, Parts of the triceps. 
c c, Pectinalis. d d, Psoas magnus. e e, Iliacus internus. /, Part of the 
glutseus medius. g, Part of the glutseus minimus, h, Cut extremity of 
the rectus femoris. i i, Vastus externus, k, Tendon of the rectus femoris. 
1 1, Vastus internus, * Sartorius muscle. * * Fleshy origin of the tensor 
vagina femoris or membranosus. Its tendinous aponeurosis covers (/) 
the vastus externus on the right side, m m, Patella, n n, Ligament or 
tendon from it to the tibia, o, Rectus femoris. p, Crurseus. q q, The ti- 
bia, r r, Part of the Gemellus, or gastrocnemius externus. s s s, Part of 
the soleus or gastrocnemius internus. t, Tibialis anticus. u, Tibialis pos- 
ticus, v v, Peronsei muscles, w w, Extensor longus digitorum pedis, xx, 
Extensor longus pollicis pedis, y, Abductor pollicis pedis. 

Fig. 2. The muscles, Glands, &c, of the Left Side of the Face and Neck, 
after the common Teguments and Platysma myoides have been taken off. 

a, The frontal muscle, b. Temporalis and temporal artery, c, Orbicularis 
palpebrarum, d, Levator labii superioris alseque nasi, e, Levator anguli 
oris, f, Zygomaticus, g, Depressor labii inferioris. h, Depressor anguli 
oris, i, Buccinator, k, Masseter. 11, Parotid gland, m, Its duct, n, 
Sterno-cleido-mastoideus. o, Part of the trapezius, p, Sterno-hyoideus. q, 
Sterno-thyroideus. r, Omo-hyoideus. s, Levator scapulae, tt, Scaleni. 
u, Part of the splenius. 

Fig. 3. The Muscles of the Face and Neck in view after the exterior 
ones are taken away. 

a a, Corrugator supercilii. b, Temporalis, c, Tendon of the Levator 
palpebral superioris. d, Tendon of the orbicularis palpebrarum, e, Mas- 
seter. f, Buccinator, g, Levator anguli oris, h, Depressor labii superi- 
oris alseque nasi, i, Orbicularis oris, k, Depressor anguli oris. 1, Muscles 
of the os hyoides. m, Sterno-cleido-mastoideus. 

Fig. 4. Some of the Muscles of the Os Hyoides and Submaxillary Gland. 

a, Part of the masseter muscle, b. Posterior head of the digastric, c, 
Its anterior head, d d, Sterno-hyoideus. e, Omo-hyoideus. f, Stylo-hyoid- 
eus. g, Submaxillary gland in situ. 

Fig. 5. The Submaxillary Gland and Duct. 

a, Musculus mylo-hyoideus. b, Hyo-glossus. c, Submaxillary gland re- 
moved from its place, d, Its duct. 

Plate VII. 

Fig. 1. The Muscles immediately under the common teguments on the 
posterior part of the body, are represented on the right side; and on the 
left side the Muscles are seen which come in view when the exterior ones 
are taken away. 



EXPLANATION OF THE PLATES OF THE MUSCLES. 



367 



Head. — A A, Occipito-frontalis. B, Attollens aurem. C, Part of the 
orbicularis palpebrarum. D, Masseter. E, Pterygoideus interims. 

Trunk. — Right side. F F F, Trapezius seu cucullaris. G G G G, Latis- 
simus dorsi. H, Part of the obliquus externus abdominis. 

Trunk. — Left side. I, Splenius. K, Part of the complexus. L, Le- 
vator scapula?. M, Rhomboides. NN, Serratus posticus inferior. O, 
Part of the longissimus dorsi. P, Part of the sacro-lumbalis. Q, Part of 
the semi-spinal is dorsi. R, Part of the serratus amicus major. S, Part of 
the obliquus internus abdominis. 

Superior Extremity. — Right side. T, Deltoides. U, Triceps exten- 
sor cubiti. V, Supinator longus. W W, Extensores carpi radialis longior 
and brevior. X X, Extensor carpi ulnaris. Y Y, Extensor digitorum com- 
munis. Z, Abductor indicis. 1, 2, 3, Extensores pollicie. 

Superior Extremity. — Left side, a, Supra-spinatus. b, Infra-spina- 
tus. c, Teres minor, d, Teres major, e, Triceps extensor cubiti. f f, 
Extensores carpi radialis. g, Supinator brevis. h, Indicater. 1,2,3, Ex- 
tensores pollicis. i, Abductor minimi digiti. k, Interossei. 

Inferior Extremity. — Right side. 1, Glutaeus maximus. m, Part of 
the Glutaeus medius. n, Tensor vaginae femoris. o, Gracilis, p p, Ad- 
ductor femoris magnus. q, Part of the vastus internus. r, Semimembra- 
nosus, s, Semitendinosus. t, Long head of the biceps flexor cruris, uu, 
Gastrocnemius externus seu gemellus, v, Tendo Achillis. w, Soleus seu 
gastrocnemius internus. x x, Peronseus longus and brevis. y, Tendons of 
the flexor longus digitorum pedis ; and under them * flexor brevis digitorum 
pedis, z, Abductor minimi digiti pedis. 

Inferior Extremity. — Left side, m, n, o, p p, q, r, s, t, v, w w, x x, y, z, 
Point to the same parts as in the right side, a, Pyriformus. b b, Gemini, 
cc, Obturator internus. d, Quadratus femoris. e, Coccygseus. f, The 
short head of the biceps flexor cruris, gg, Plantaris. h, Popliteus. i, 
Flexor longus pollicis pedis. 

Fig. 2. The Palm of the Left Hand after the common Teguments are 
removed, to show the Muscles of the Fingers. 

a, Tendon of the flexor carpi radialis. b, Tendon of the flexor carpi ul- 
naris. c, Tendons of the flexor sublimis perforatus, profundus perforans 
and lumbricales. d, Abductor pollicis. e e, Flexor pollicis longus. f, 
Flexor pollicis brevis. g, Palmaris brevis. h, Abductor minimi digiti. i, 
Ligamentum carpi annulare, k, A probe put under the tendons of the flexor 
digitorum sublimis; which are performed by 1, the flexor digitorum profun- 
dus, mmmm, Lumbricales. n, Abductor pollicis. 

Fig. 3. A Fore-View of the Foot and Tendons of the Flexores Digitorum. 

a, Cut extremity of the Tendo Achillis. b, Upper part of the astragalus, 
c, Oscalcis. d, Tendon of the tibialis anticus. e, Tendon of the extensor 
pollicis longus. f, Tendon of the peroneus brevis. g, Tendons of the 
flexor digitorum longus, with the nonus Vesalii. h h, The whole of the 
flexor di<ritorum brevis. 



368 EXPLANATION OF THE PLATES OP THE MUSCLES. 

Fig. 4. Muscles of the Anus. 

a a, An outline of the buttocks, and upper part of the thijrhs. b The 
testes contained m the scrotum, c c, Sphincter ani. d, Anus, e, Leva! 
tor am. ff, Erector penis. gg , Accelerator uriiue. h, Corpus caver- 
nosum urethrae. K v-aver 

Fig. 3. Muscles of the Penis. 
Tm„ a W b e^ems. , ' P0in ' the6amelSi " Fis - 4 - C > Sphincte -«■ «• 



PART IV. 

OF THE GENERAL INTEGUMENTS, OR OF THE CELLULAR 
MEMBRANE, AND THE SKIN.* 

CHAPTER X. 

OF THE CELLULAR MEMBRANE. 

That substance which is situated between the skin and the 
muscles, which is insinuated between the different muscles, and 
between the fibres which compose them ; which also connects 
the different parts of the body to each other, is denominated the 
Cellular Membrane, or Tela Cellulosa. 

* The integuments of the body consist of the skin or dermoid tissue, and of that 
portion of the common cellular tissue which is subcutaneous, and seems to con- 
nect the skin, to the subjacent parts. The cellular tissue is loose and elastic, and 
by this simple arrangement, the skin is loosely connected to the muscles, and not 
forced to follow them rigidly in their contractions ; thus, the roundness of the sur- 
face and the smoothness of the skin, is in a great measure preserved. The skin 
is directly continuous in the mouth, nares, urethra, vagina, anus, and external au- 
ditory meatus, with the mucous membranes, lining the interior of all the cavities 
of the body. The continuation or conversion of one into the other at these orifices, 
is so gradual as to be almost insensible, as will be more carefully shown under the 
head of mucous membrane. For this reason, by many of the French anatomists, 
the skin is called the external tegumentary membrane, and the mucous membrane 
the internal tegumentary membrane. The basis or derma of the two tissues being 
considered with some modification the same, the cuticle analogous to the undried 
mucous of the latter membrane, the papilli and sebaceous glands of the skin, to 
the villi and follicles of the latter membrane. 

This division into two membranes is not new; it may be traced to the time of 
Galen, but we are indebted for its re-introduction to science, principally to Bonn, 
and Bichat. The physiological and morbid sympathies of the two membranes 
have been long known, as being more intimate, than that which exists between 
any two thoroughly distinct tissues in the human body. — p. 



370 THE CELLULAR MEMBRANE. 

As it extends over the whole of the body, and is most inti- 
mately connected with the skin, it is considered as one of the 
integuments, although it is found in great quantities in some of 
the internal parts. 

It appears to be composed of membranous laminae, exquisitely 
fine and delicate in their structure, which are so connected to 
each other that they compose cells or cavities of various forms 
and sizes. 

When these cavities are empty, this arrangement of the cellu- 
lar membrane is not apparent ; but when they are distended by 
water or air it is very evident. 

The laminae which pass from one contiguous part to another 
are of different lengths, according to the motions performed by 
the different parts ; thus,, about the muscles and their tendons 
they are of considerable length, and between the coats of the 
eye they are very short. 

In some places, these laminae are compressed together, and 
form a dense membrane somewhat resembling tendon ; but 
whenever they are separated from each other, they appear pel- 
lucid, and extremely delicate. 

— The cellular tissue serves as the connecting medium of 
other tissues, and might very properly be called the connecting 
tissue. In the fetus, when all the parts are soft, and as yet un- 
formed, it presents the aspect of mucus, filling up the interstices 
of the other nascent organs. Hence Bordeu and Meckel, have 
denominated it the mucous tissue, and supposed that its cellular 
and membranous structure, was produced mechanically by the 
traction of surrounding air, or the infiltration of fluid. The term 
mucous, however, is inappropriate and confusing, and applicable 
only to the nascent state of the organ ; it has been proved by mi- 
croscopical investigations to be erroneous when the develope- 
ment of the tissue is complete. 

— The ultimate elements of all cellular tissue are fibres, not 
merely globules or lamellae. These primary fibres, are among 
the most minute constituent elements of the human body. Their 
diameter, according to the microscopical measurements of Jor- 
dan, is the i4 Voth part of an English line. They are transparent. 



THE CELLULAR MEMBRANE. 37 J 

and yield gelatine on boiling, in which respect they correspond 
with the primitive fibres of tendons. Treviranus has recently 
asserted from microscopical observations, that they are hollow 
cylinders, which terminate by one extremity in the minute lym- 
phatic vessels.* This, which possibly may be the case, and is 
supported by the opinion of Fohman, wants confirmation from 
other observers. 

— These fibres of the cellular tissue, are united so as to form 
lamellated membranes which cross each other in all directions, 
and produce an irregular interlacement, constituting a series of 
cells, which communicate together. — 

These lamina?, when ifi a healthy state, appear to have no 
sensibility; but so many nerves pass through them, that pain is 
generally felt when incisions are made in the cellular mem- 
brane. 

No vessels can be seen in their composition when they are 
free from disease, although many pass through them. On this 
account they have been considered by some very respectable 
physiologists as inorganic; but there are good reasons for regard- 
ing this sentiment as erroneous. 

If a portion of cellular membrane, in the living subject, be 
brought into view by a surgical operation or a wound, and be 
allowed to remain some time covered by an emollient cataplasm, 
or a soft plaster, a complete change of colour will gradually 
take place; it will become uniformly red, in consequence of the 
great number of minute vessels into which blood has penetrated 
during inflammation; and granulations will form on its surface. 

These vessels must have existed previously in the sound state 
of the membrane, and conveyed a transparent fluid; although 
no structure of this kind was visible. This single fact therefore 
proves completely its organization. 

In some parts of the body, this cellular membrane appears to 
be moistened by a small quantity of fluid, or halitus, in its cells ; 
which seems merely sufficient to keep it soft and flexible. In 
other places it is loaded with fat. 

* Mailer's Archives for 1834, p. 410. 

t Vide Breschet, sur le Systeme Lymphatique, etc. Paris, 1836. 



372 THE CELLULAR MEMBRANE. 

There is great reason to believe that the fat is contained in 
cavities which are somewhat different from the ordinary cavi- 
ties of the cellular membrane. 

The cells or cavities which contain the moisture or halitus 
communicate with each other, over the whole body. Thus, air 
insinuated into the cellular membrane exterior to the pleura, in 
consequence of a fractured rib, will be diffused over the whole 
body ; and produce the disease called emphysema. In a patient 
who is affected with that species of dropsy called anasarca, a 
portion of the fluid will be effused in the head and upper parts of 
the body, after he has passed a night in bed in a horizontal po- 
sition ; but after he has been in an erect position for some time, 
the fluid will be accumulated in the legs and feet, or most de- 
pending parts of the body, in consequence of its gravity. 

It is well known in dissecting-rooms, that the effused water 
may be completely discharged from anasarcous subjects, by 
making incisions in the feet and placing the subject erect. 

Blood effused in the cellular membrane is sometimes dispersed 
in the same way ; an ecchymosis often appears in the eyelids in 
consequence of a contusion on the upper part of the head ; and 
similar appearances occur in almost every part of the body, in 
consequence of effusion of blood at a distance from them. 

The fat or adipose matter is not diffused in this manner : 
wherever it is first effused, it remains, uninfluenced by gravity, 
or the ordinary pressure. 

Fat is not observed in every part of the body ; it is never 
seen in the cellular membrane of the eyelids ; of the penis ; of 
the lungs ; or of the parts within the cranium ; as well as of se- 
veral other places. The inconvenience which would result 
from the accumulation of fat in these places is very obvious : and 
it is equally certain that the cellular membrane in them must be 
different from that in which fat is produced. 

From these peculiar circumstances, relative to the adeps, it 
has been inferred, that there was a peculiar apparatus for the 
production and retention of fat, superadded to the cellular mem- 
brane ; and some anatomists, with a view to precision, have 
called the part containing fat, Adipose Membrane, and the other 



ADIPOSE TISSUE. 373 

part Reticular Membrane.* They state that in dropsical sub- 
jects, who arc much emaciated, the membrane, which in a 
healthy state contained adeps, is more ligamentous than the or- 
dinary cellular membrane. 

It seems to be proved, by reasoning, that there must be a con- 
siderable difference between these different parts of the cellular 
membrane ; but it ought to be observed that those parts of the 
omentum which are especially appropriated to the production of 
adeps, do not exhibit any peculiarity of structure. 

This adipose substance is distributed in unequal proportions in 
different parts of the body. In corpulent persons there is a con- 
siderable quantity of it, immediately under the skin, and espe- 
cially under the skin of the abdomen. 

It is also between the muscles, in the orbits of the eyes ; in 
the omentum and mesentery ; in the joints and the bones ; as 
well as about the kidneys, and heart also, in elderly persons. In 
the foetus, and for some time after birth, it appears to be con- 
fined to the parts immediately under the skin, but it soon be- 
comes more diffused. — The fat in the adipose tissue, is unor- 
ganised, and at the common temperature of the human body, is 
almost fluid- On the latter account it produces the softness and 
smoothness of the exterior, particularly obvious in obese indivi- 
duals. Its use, probably, besides contributing to the roundness 
and softness of the exterior, is in part to protect the body against 
the extremes of heat and cold, in consequence of its being a 
bad conductor of caloric. It may be considered also, as a de- 
posit of nutriment held in reserve, to be dissolved and taken up 
again by the absorbents, during fasting, or when any wasting 
disease has impaired the functions of nutrition. — 

It is observed by dissectors that there are no subjects, how- 
ever emaciated, who are entirely free from fat; except those 
who have been affected with anasarca. 

The cellular membrane has been already observed to form 
granulations very promptly; and it has been asserted that the 
granulations, which arise from all the different parts of the body 

* See remarks on the cellular membrane, &c., by Dr. W. Hunter, in the Lon- 
don Medical Observations and Inquiries, vol. ii. 
vol. i. 32 



374 CELLULAR TISSUE. 

when wounded, originate from the cellular membrane in those 
parts. 

Whether this proposition be true or not, to the extent above 
stated, it is a fact that granulations, in some instances, seem to 
have a cellular structure ; as the following case will prove. 

A patient, with a compound fracture of the leg, which was 
attended with a large wound, covered with luxuriant granula- 
tions, was attacked with an cedematous swelling of the limb, 
which increased suddenly to a great degree. While this was 
going on, the granulations on the surface of the wound tumefied 
with the limb; and, upon examination, appeared somewhat pel- 
lucid, with an effused fluid indenting by pressure, precisely as the 
skin was indented. 

The cellular membrane appears to have a most intimate con- 
nexion with the skin ; and cannot be completely separated from 
it by dissection. It is said that in certain cases of disease, where 
it is reduced to a slough, while the texture of the skin remains 
unchanged, as in some species of anthrax or carbuncle, this sepa- 
ration may be completely effected. In such cases the under 
surface of the skin will appear to be composed of pits or excava- 
tions, which penetrate very deep into its substance, and were 
occupied by the cellular or adipose membrane while it was in its 
natural condition. 



THE SKIN. 375 



CHAPTER XI. 

OF THE SKIN. 

The skin is composed of three dissimilar lamina, which are denominated the 
Cutis Vera, the Rete Mucosum, and the Cuticula. 

Of the Cutis Vera. 

The innermost of the above-mentioned lamina is much more 
substantial than the others, and therefore is called Cutis Vera. 

It is an elastic, dense, and strong membrane ; which contains 
in its texture a large proportion of fibres that appear to be tendi- 
nous, and are woven together in an intricate manner.* 

Blended with these fibres is an immense number of vessels 
which enter into the texture of the skin; these vessels do not 
generally convey red blood, and therefore they are not very 
visible; yet they may be readily brought into view, by the appli- 
cation of rubefacients during life ; and by fine injections, in the 
dead subject. Their existence is also demonstrated in the vigor- 
ous infant, at birth, by the universal redness of the skin, which is 
observable at that time. 

Nerves are also distributed to every part of the skin. They 
can be traced to it very easily; and as there is no part of the 
skin into which the finest needle can be pushed without pain, it 
is certain that their distribution must extend to every part. 

It is highly probable that the processes of absorption and ex- 
halation are effected by small vessels which originate or terminate 
on the surface of the skin, and of course form a part of its 
texture. 

The skin, thus constructed, extends over the whole of the 

* These fibres hold a middle station between ligamentous and common cellular 
tissue, and are supposed to consist of the latter in a very compacted state. The 
meshes, which they leave when woven together, allow of the introduction of vessels 
and nerves to the papilla; and to the outer surface of the catis vera. — p. 



376 CUTIS VERA. 

body, and is continued into those cavities which open upon the 
surface, as the mouth, nose, &c, although its texture changes im- 
mediately upon its reflection. 

It varies in thickness in different parts ; thus, it is thicker on 
the back than the front of the body. It is thin on the insides of 
the arms and leg, where opposite surfaces touch each other.* 

It is, in general, thinner in women than in men. 

The elasticity of the skin is made evident by its yielding to 
distention, and returning to its usual size ; as in pregnancy, dropsy, 
&c. ; but it is particularly demonstrated in some cases of par- 
turition, when the skin of the perinaeum stretches immensely, 
and, after labour, very quickly recovers its size. 

The external surface of the skin is very generally divided by 
superficial grooves or sulci, into small spaces of various angular 
forms ; most commonly rhomboidal. On the palms of the hands 
and soles of the feet, instead of these figures, we perceive the 
whole surface composed of furrows and ridges, which, in some 
places, are rectilineal, and, in others, oval and spiral. 

There are also a number of depressions or grooves which 
seem formed to accommodate the various articulations, particu- 
larly about the fingers and toes. 

There are other furrows, occasioned by muscles, as those on 
the forehead : and some depend on the subjacent cellular mem- 
brane. 

On the external surface of the true skin, when the two exterior 
laminae are removed, many papillae are to be seen. They differ 
in size in different parts of the body; they are vascular, and, on 
the ends of the fingers, appear like villi, when examined by a 
magnifying glass. 

There are many perforations or pores to be seen on the skin 
with the naked eye, which are probably the ducts of sebaceous 
glands, and the passages which transmit hairs. Other pores, 
different from either of these, are to be seen when magnifying 
glasses are used ; as those on the fingers; these probably are the 

* The thickness on the back, is about double what it is on the front of the 
body. — p. 



SEBACEOUS FOLLICLES. 377 

exhaling or absorbing pores, but their connexion with the vessels 
which perform these functions has not yet been demonstrated. 

The internal surface of the skin, when carefully dissected 
from the subjacent cellular membrane, in a subject of ordinary 
corpulency, appears to have some adipose substance in its tex- 
ture; but, as has been already mentioned, when the cellular 
membrane is destroyed, these portions of adipose matter disap- 
pear, and the surface of the skin appears pitted. It is probable 
that this connexion of the cellular membrane and skin may oc- 
casion that delicacy of skin which appears in some hydropic 
patients. 

In some places on the under surface of the skin are small 
glands called miliary, from their resemblance to the millet seed; 
these glands are supposed to secrete a sebaceous matter, but they 
are not so general as has been supposed. 

There are sebaceous follicles or ducts, which open on the ex- 
ternal surface of the skin, and contain an oily substance, which, 
sometimes, has the consistence of suet or tallow; when these 
ducts are filled with sebaceous matter, their orifices are often 
covered by a black substance, which accidentally adheres to the 
surface of the matter, and forms very small black spots in the 
skin. These often occur on the nose and ears, and may be removed 
by pressing out the sebaceous substance, which rises up in the 
form of small worms. Sometimes this secretion accumulates in 
the ducts in such quantities, that it forms small tumours in the skin. 

— Fig. 23, is a portion of skin cut vertically 
from the nose of an old man, in order to show the 
sebaceous follicles and their ducts, which are 
magnified to about double their natural size. 
They are found in all parts of the body, with the 
exception of the palms of the hands and soles of the feet; but in 
many parts only become visible to the naked eye, in diseased 
conditions of the skin. They are most numerous in the face, 
behind the ears, and in the arm-pits and groin. There is a 
strong analogy between them and the follicles of mucous mem- 
branes. 

32* 




378 



SEBACEOUS FOLLICLES. 




Fig. 24. — Fig. 24, represents the orifices of the 

sebaceous glands, as they are seen in 
the nose, after it has been deprived of 
its epidermis. Each follicle consists of 
a simple depression or doubling inwards 
of the cutis vera, which becomes more 
vascular and thin where it forms the 
walls of the follicle. The sebaceous 
follicles, according to E. Weber, are 
much larger and entirely distinct from 
those forming the bulbs of the hairs. 
The latter, too, are situated more 
deeply, being often found in the subcu- 
taneous cellular tissue. They differ also, 
according to him, in their structure; 
each sebaceous follicle being composed 
of four or five compartments or cells agglomerated together. 
They are also larger than those of the bulbs of the hairs; the 
largest diameter of a sebaceous gland, (the transverse,) observed 
by Dr. Weber, was three-fourths of a line. — 

Muscular fibres have been supposed by some persons to exist 
in the skin, but such fibres have never been demonstrated in it. 
The skin of the scrotum is often much contracted, but the fibres 
which produce this effect are very visible in the cellular mem- 
brane, and have a muscular appearance. 

Although the skin is not muscular, it sometimes changes its 
appearance in a surprising manner. 

When the surface of the body is suddenly exposed to cold, or 
when the chill of fever exists to a considerable degree, the skin 
will contract very sensibly, and, at the same time, a great number 
of conical papillas will project from its surface. This constitutes 
the Cutis Anserini; and is supposed to be produced by a sudden 
contraction of the vessels in the skin, which forces out their 
contents, and of course, diminishes its bulk ; while the papillas do 
not contract in the same degree, and, therefore, are somewhat 
projected. 

When the skin is free from disease, the two exterior laminae, 



RETE MUCOSTTM. 379 

(Cuticle and Rete Mucosum,) maybe separated from it completely, 
after maceration or putrefaction, and the surface will appear 
smooth ; but, in an inflamed skin, a net-work of vessels has been 
injected ; which is considered, by Mr. Cruikshank* as an ad- 
ditional lamen. In this lamen, the pustules of small-pox originate. 
When the skin is injected, they appear to be formed at first by 
very small vessels, arranged in a radiated manner, with a white 
uninjccted substance in the centre, which is supposed to be a 
slough, occasioned by the irritation of the variolous matter. Mr. 
Cruikshank, after removing this lamella, was able, by continued 
maceration of the same skin, to separate another, which was also 
vascular. It is to be observed that this skin had been preserved 
for some time in spirits, and was macerated in putrid water a 
week during the heat of summer, before the first lamella was 
removed. 

The colour of the healthy skin is invariably white, when all 
the lamellae exterior to it are removed. This is the case not 
only with the European, but with the blackest African, and the 
people of all the intermediate colours. 

The variety of colours in the human species depends upon the 
lamella next to the cutis, which is now to be described. 

Of the Rete Mucosum. 

Immediately in contact with the external surface of the cutis 
vera is a thin stratum, of a pulpy or mucilaginous consistence, 
which appears to be spread uniformly over it, but cannot be de- 
tached without deranging its own texture.f 

It can be best examined after the cuticle is raised in a blister. 
In this case it appears like a pulpy substance, spread upon a 
membrane of a soft and delicate texture. This is the Rete, or 
Corpus Mucosum. 

In this pulpy substance resides the pigmentum, or colouring 
matter, which gives the peculiar complexion to the different 
races of men. The cutis vera is white, and the cuticle is nearly 

* See Experiments on Insensible Perspiration, &c. by W. Cruikshank. 
t It lias been asserted that the rete mucosum of the scrotum can sometimes be 
exhibited in a separate state. 



380 R ETE MUCOSUM. 

transparent in them all; but this substance is black in the negro; 
copper-coloured, yellow, or tawny, in many of the Asiatics ; and 
yellow, with a tincture of red, in the aborigines of America : 
while it is transparent, or whitish, in the people of Europe and 
their descendants. 

It can therefore be best examined in the negroes ; and if it be 
inspected immediately after the cuticle of a blister is removed, 
it will appear as above described, with a black matter diffused 
through it. 

The particular structure of this substance has not been ascer- 
tained, although anatomists have paid a good deal of attention 
to it. It is generally believed by them that no vessels can be in- 
jected in it; but Dr. Baynham of Virginia, while he was en- 
gaged in anatomical pursuits in London, made a preparation 
which excited the attention of the British anatomists, on account 
of its particular relation to this subject. 

He injected one of the lower extremities, the os femaris of 
which was diseased with an exostosis ; and with a view to an 
examination of the lamina of the skin, he removed a portion of 
it from the leg ; and after immersing it a few seconds in boiling 
water, to thicken the lamina, he macerated it in cold water for 
some days. Upon separating the cuticle, after this treatment, 
he discovered a texture of vessels on the surface of the cutis 
vera, which was distinct from the cutis itself. This has often 
been mentioned as injection of the rete mucosum. 

It is to be regretted that Dr. Baynham, who is particularly 
qualified to decide, has not published his opinion on the subject. 
Mr. Cruikshank, to whom he afforded the most satisfactory op- 
portunity of examining his preparation, believes that the afore- 
said vessels were not a part of the rete mucosum ; but that the 
rete mucosum was to be seen on the epidermis, (being raised 
with it when it was separated from the cutis,) while this texture 
remained on the surface of the cutis. He considers these vessels 
as belonging to the additional lamellae already mentioned, of 
which he says Dr. Baynham is the discoverer. 

There is therefore every reason to believe that there is a tex- 



CHANGE OF COLOUR. 



381 



ture of vessels, either in the rete mucosum, or between the cutis 
vera and the rete mucosum. 

After putrefaction, or maceration for a long time, the cuticle 
separates readily from the cutis vera ; and the rete mucosum 
sometimes adheres to the skin, and sometimes to the cuticle. If 
the parts are much softened by putrefaction, the rete mucosum 
can be washed away, like the pigmentum nigrum of the eye ; 
leaving the cutis white, and the cuticle nearly transparent. 

In the negroes the black colour of the rete mucosum is greatly 
diminished, on the palms of the hands, and soles of the feet, and 
under the nails ; but it is perceptible. It is said that the black 
colour does not appear in the cicatrices of the blacks. This is 
the fact with respect to recent cicatrices ; but those of long 
standing are often dark-coloured, although not so black as the 
original skin. The pits of the small-pox in their skins, although 
white at first, become finally as dark as the original surface. 

In Europeans and their descendants the colour of the rete mu- 
cosum becomes darker, as they are more exposed to the air and 
the rays of the sun ; and soon changes again to its original fair- 
ness, by confinement to the house. 

In negroes the skin loses some of its deep glossy black colour 
during the winter season of cold climates, and recovers it again 
in summer. 

The rete mucosum sometimes undergoes very important 
changes; there have been several instances in the United States, 
where large portions of the skin of the African have changed 
from black to white ; owing probably to an absorption of the 
black pigment from the rete mucosum ; or, perhaps, to an ab- 
sorption of the rete mucosum itself. 

There is now in Philadelphia a female, between thirty and 
forty years of age, in whom this process is going on. One of 
her parents was a negro and the other a mulatto ; and her ori- 
ginal complexion accorded with her origin. But a change of 
colour began during her childhood, in small spots, which have 
gradually increased so much, that at this time the whole of her 
body and limbs are nearly white, with the exception of her hands 
and feet. A large proportion of her face is also white, and the 
remainder of it much lighter than it was originally. At this 



382 CHANGE OF COLOUR. 

time, some part of her face has an unnatural whiteness ; but the 
skin of her forearms appears like that of a European in a per- 
fectly healthy state. This change of colour is attended with no 
unusual sensation ; so that if she did not see the alteration, she 
would not suspect that her skin was any way different now from 
what it had originally been. She does not appear sensible that 
the white parts are more susceptible of irritation from the rays 
of the sun than they were originally ; but they are so much 
covered by her dress that the experiment has not yet been fairly 
made. 

The first appearance of a change is slight diminution of the 
dark colour ; this change goes on gradually, and then small 
spots appear, which are perfectly white. They gradually in- 
crease, and run into each other, and thus a large white spot is 
formed. 

In a former case, where this process had gone on to a great 
extent, it is said that the black pigment was again deposited, and 
the skin resumed its original blackness. 

These circumstances in negroes have been considered as great 
deviations from the ordinary course of nature, but a process 
very analogous to it sometimes goes on in persons who are 
white. Thus, there are some in whom the skin becomes much 
browner than natural in some parts of the body, particularly on 
the arms; and in these brown portions, spots are formed which 
are much more white than the natural colour of the skin. 

In such cases there appears to be a deposition of colouring 
matter in the rete mucosum of the brown places ; while the 
white spots are rendered more white than natural, either by an 
absorption of the rete mucosum, or by a deposition of whiter 
matter in it. 

The colour of the rete mucosum sometimes undergoes a tem- 
porary change in particular places. Thus, at a certain period 
of pregnancy, a dark circle forms round the nipple. 

In some cases, where the peculiar whiteness occurs, the skin 
becomes very susceptible of irritation from the rays of the sun ; 
so as to be blistered, if exposed to them for a short time ; this 
circumstance renders it probable that the colouring matter in 
the rete mucosum of the blacks, was originally designed to pro- 



ALBINOES. 383 

tect their skins from the very powerful rays of the sun to which 
they are exposed. 

There are some persons to be found, amongst most of the dif- 
ferent races of men, who are born with this peculiar whiteness 
of the whole skin, which continues during life. In these per- 
sons, the hair has a remarkably white colour, and the eyes are 
without the pigmentum nigrum. They appear to be in a state 
of imperfection, and are unable to endure the ordinary light of 
day. They are generally designated by the epithet of Albinoes. 

The texture which exists between the cutis vera and the epi- 
dermis is probably the principal seat of several important cuta- 
neous diseases ; as the Scarlatina Pemphigus, &c* and from 
what has been stated, there is good reason to believe that the 
small-pox, also, commences in it. It is, therefore, much to be 
wished that its structure was more precisely ascertained. 

— The variety of diseases which have their seat in the skin, as 
well as the important functions which it exercises in health, have 
led modern anatomists to believe that it was formed of more 
than the three layers, that Malpighi assigned it, and induced 
them to investigate its structure with scrupulous care. From 
the innate difficulties of the subject, its anatomy cannot as yet, 
however, be considered as satisfactorily made out, for its inves- 
tigators have too frequently resorted to hypothesis, when the 
means of demonstration failed them. The doctrines of the 
learned and judicious Malpighi, which have been admirably de- 
tailed above, were generally admitted by anatomists, till M. 
Gaultier,f a mere student of medicine, full of zeal and candour 

* In severe cases of the scarlatina, at the termination of the disease, large por- 
tions of the cuticle are sometimes detached from the cutis, so that several practi- 
tioners have seen the whole cuticle of the hand come off like a glove. As the 
texture of the cutis docs not appear to be altered in these cases, and the cuticle is 
also unchanged, the cause of this separation must exist in the intervening struc- 
ture which connects them. 

t Gaultier, whose opinions have been adopted in the main by Beclard, Blandin, 
Cloquet and others, would, if he had lived, most probably done much towards sim- 
plifying and perfecting his views. Appointed army surgeon immediately after 
his graduation, he fell a victim to the disasters of the Russian campaign. The in- 
vestigation has, however, been taken up by Dutrochct who extended it to the skins 
of quadrupeds, by several of the German and Italian anatomists, and lastly by 
Breschet and Roussel de Vauzeme. The last have made it a subject of elaborate 



384 STRUCTURE OF THE SKIN 

published in 1813 his researches on the skin, which, though im- 
perfect in some respects, went far towards establishing its real 
structure. 

— The reie mucosum, which Malpighi considered a simple coat- 
ing of mucus, between the cutis vera and cuticle, a sort of varnish 
covering the papillae, was considered by Bichat as essentially 
formed of vessels, and divided by him into two vascular layers, 
one over the other, in the outermost of which was placed the 
colouring matter or pigment. But Gaultier, from his observation 
of the skin of the negro, and Dutrochet from that of quadrupeds, 
consider it composed of many distinct parts. Gaultier selected 
for observation the skin of the heel of a negro where the cuticle is 
thickest, but which he thought differed in no other respect from 
the skin in other parts of the body. 

— This figure is a magnified representation of a section of the 
Fig. 25. skin cut obliquely in regard to its 

nmTfmV^FlF)^^ , thickn , ess ' and transversely to the 
a^»^^%?^yy^???^!rt ines * orme d D y tne papillae. In 

this, according to Gaultier, we see 
at a, the lower surface of the derm, 
or cutis vera. 1, The prominences or asperities of the derm, form- 
ing the papillae, each one with a slight depression upon the top. 
2, Immediately above these and continuous with them we see a 
series of vascular fasciculi surmounting these prominences, called 
bloody pimples, (bourgeons sanguins.) 3, The tunica 
Fig. 26.* albida profunda, covering these papillae upon their top 
and sides, and united to the upper surface of the derma, 
and composed entirely of white vessels, (serous capilla- 
ries.) 4, Gemmules; a sort of membrane so named 

microscopical research, not only in man, but in the whale and many of the larger 
animals. The views of Gaultier thus modified and improved, are well deserving 
of study as the most satisfactory yet given, though, from the doubt which is always 
attached to microscopical observations, they must be looked upon rather as the 
probable than the proven structure. — p. 

* Fig. 26 — Is a representation of the skin, and the basis of the papilla?, the 
latter surmounted by the vascular villi or fasciculi, {bourgeons sanguins.) The 
space between these fasciculi is filled up, in the natural state of the parts, accord- 
inw to Gaultier, with the tunica albida profunda. 





ACCORDING TO GAULTIER. 3Q5 

from its undulations, excavated on its internal face, which covers 
in the tunica albida profunda. This is the seat of the colouring 
matter of the skin, and each one receives two of the bifid tops of 
the papilla;, called bourgeons sanguins. 5, Tunica albida superfi- 
cialis, which covers over the gemmules, and also formed entirely 
of white vessels. 6, The external face of the skin, which is only 
the dried surface of the tunica albida superficialis, or the proper 
epidermis. Gaultier considers four of these layers as belonging 
to the rete mucosum; the perpendicular vascular fasciculi (bour- 
geons sanguins,) the gemmules Fig. 27.* 
and the two white tunics. 



— The first and second of these 



four, correspond with the two ' n ^^ ,mmmm ^™^mmimmm'm0 m 
vascular layers which Bichat assigns to the rete mucosum ; and 
the views of Gaultier differ from this writer's in his adding two 
more tunics, tun. albid. profunda, and tun. albid. superficialis. But 
the vascular fasciculi, as Dutrochet and Beclard have asserted, be- 
long to the cutis vera, and form a part of the proper papillary 
body; and were probably the parts injected by Baynham and 
Cruikshank— thus leaving the rete mucosum formed of three 
layers. Thus modified, Gaultier's researches have been adopted 
by many writers. 

— But there were not wanting others who entertained different 
views. Gall believed the rete mucosum a nervous expansion for 
the reception of tactile impressions ; an opinion purely hypotheti- 
cal and erroneous; Chaussier, that the skin was composed of 
but two parts, the dermis and epidermis, and that that, which had 
been called the rete mucosum was probably a. part of the dermis ; 
Blandin,f that the rete mucosum, consisting of three layers ac- 
cording to Dutrochet placed between the papillary bodies and 
the epidermis, had neither vessels or nerves, was a product of 
secretion from the papillae, like the epidermis, and formed in fact 
a second epidermis thicker and softer than the external, and that 
it had no more vitality than the hair and nails. 

• Fig. 27, is a representation of the derm, or cutis vera, with a line of promi- 
nences on its upper surface, constituting the basis of the papillae. 
t See Anat. Gencrale of Bichat. Paris, 1831.— p. 
vol. i. 33 



386 STRUCTURE OF THE SKIN 

— Breschet and Roussel de Vauzeme,* have in this uncertain and 
imperfect state of our knowledge, endeavoured with the aid of 
the scalpel and the microscope, to determine positively its struc- 
ture. Their researches have been extended not only to the skin 
of man, but to that of whales and others of the cetaceas. The dis- 
coveries which they allege to have made are surprising, and 
though their researches appear to have been made with much 
labour and ingenuity, their confirmation or overthrow must de- 
pend upon the investigation of others equally familiar with the 
same instruments. 

— But it must not be forgotten that such high magnifying pow- 
ers as they have used, expose the most wary and honest observer 
to optical illusions. This cause led De la Torre, to assert that 
the globules of the blood were annular. 

— According to these writers, the skin consists of but two layers. 
The derm, or cutis vera, and an external layer, which they call 
indifferently epidermis, corneous matter, corneous tissue, or epi- 
dermic layers, and which comprises the rete mucosum and epi- 
dermis of other writers, which they consider composed of the 
same substance, mucus, in a greater or less state of desiccation. 
It is, however, composed of many distinct parts, not arranged in 
the form of layers. Fig. 28, represents an imaginary scheme 
or plan, in which they have placed together the constituent parts 
of the skin, the existence of which they had proved separately 
under the microscope. 

—Thus, a is the derm, b, The corneous or horny epidermic 
matter, c, The vessels and nerves which go out from the der- 
mis, d, Space filled up by their capillary branches, e, Ner- 
vous or tactile papillae. The diapnogenous, or sudoriferous ap- 
paratus, composed of a glandular parenchyma, /, and of spiral 
sudoriferous canals, g. The glandular or secretory organ is in- 
closed in the substance of the skin, and the canals pass up be- 
tween the papilke and open obliquely on the surface of the 
epidermis, constituting the microscopical orifices, from which we 

* Nouvelle recherches sur la structure de la peau, par G. H. Breschet and Rous- 
sel de Vauzeme.— Paris, 1835.— p. 



ACCORDING TO BRESCHET AND ROUSSEL DE VAUZEME 



387 



Fig. 28. 




see the sweat exuding on the palms of the hand, and soles of the 
feet, h, The inhaling apparatus, or absorbent canals, which re- 
semble in many respects the lymphatic vessels : they are situated 
in the corneous matter or rete mucosum ; they are seen to com- 
mence under the most superficial layer of the corneous matter 
which forms the cuticle; no mouth or orifices, and it is impossi- 
ble to say, whether they commence in the form of a cul de sac 
or not. They pass down between the papillae, by the side of the 
sudoriferous canals, and communicate with a net-work of ves- 
sels, which they believe to be lymphatics mixed up with veins, 
spread upon the surface of the derm.* i, The organs which 
secrete the mucus of which the rete mucosum and cuticle is 
formed, or blennogenous apparatus; this consists of a glandular 
parenchyma situated in the thickness of the derm, and of short 
excretory canals k, which deposit the mucous matter between the 
bases of the papillae. The chromatogenous organs or glands, 
which secrete the colouring matter or scales, run parallel with, 

* The existence of these inhalent vessels, from some observations I have made 
with a very powerful microscope, I should consider extremely doubtful.— p. 



388 STRUCTURE OF THE SKIN 

and immediately below the grooves on the surface, and between 
the papilli, which they are also placed a little below. The ends of 
them, marked by a collection of dots, can of course only be seen 
in the plan, in consequence of their running parallel with the 
grooves, and between the parallel ranges of papillae. 
— They consist of a glandular parenchyma, receiving an abun- 
dance of capillary vessels from the derm below, and possess- 
ing excretory canals above, which throw upon the surface of 
the derm, the colouring principle, which is mixed with the soft 
and diffluent corneous or mucous matter, thrown up by the 
blennogenous apparatus. From this mixture results the pre- 
tended rete mucosum of Malpighi, and the epidermis or cuticle. 
From this apparatus is also produced, they think, the horns, 
scales, spines, bristles, hair, wool, hoofs, nails, etc. of different 
animals. It is solidified in successive couches, to the right and 
left, as seen in the section across the grooves, 7; but in the longi- 
tudinal section m, these layers present a series of straight lines 
one above another like the leaves of a book. 
— In consequence of this arrangement, the corneous matter, when 
macerated, throws off layer after layer. The superior face of 
the epidermis presents grooves, as represented at n, which cor- 
respond to the interpapillary grooves of the derm, o, Are the 
prominent ridges in the cuticle formed over the papilli, separated 
by transverse grooves, p, at the bottom of which are found 
the pores of the sudoriferous canals, e, Are the vessels and 
nerves which enter into, or go out from the derm, d, An inter- 
val filled up by capillary filaments. 

Of the Derm. 

— The external surface of the derm, is lined by a very thin ad- 
herent membrane, which is reflected over the tops of the papil- 
lary bodies and forms their neurilema. The horny or epidermic 
matter is secreted in the grooves between the papilla, is moulded 
around all the inequalities, the form of which is exactly impressed 
on all the layers of the epidermis. In serpents, the derm, has a 
singular arrangement ; it is elevated in imbricated projections, 



ACCORDING TO BRESCHET AND ROUSSEL DE VAUZEME. 399 

covered by a thin layer of epidermis ; these are called scales. In 
fishes, on the contrary, the surface of the derm is smooth, and 
the scales are formed only of the horny matter. The derm is a 
membrane, the fibres of which are solidly interlaced together, 
with interstices for the passage of vessels, nerves and canals, 
and in which are lodged many organs, as has been shown in the 
plan, page 387.* 

Of the Papillary Body, or JVeurothelic Apparatus-^ 

— This consists of a series of little prominences on the upper 
surface of the derm, cleft at the top into two portions, each of 
which is composed of a bundle of nerves and vascular filaments, 
bourgeons sauguins of Gaultier. The form of each papilla is 
that of a cone. The base is expanded in the upper surface of the 
derm, and its two prominences or villi, terminating in a rounded 
point, are received in the horny layers of the epidermis, like a 
sword in its sheath, (see page 390.) 

— The direction of the papilla is slightly oblique in the epi- 
dermic layers, as seen in Fig. 29. J The nerves are here seen 
passing up into the papilla through the dermis; the vascular 
branches which accompany them are not here represented. 
The papilla first gets a neurilematic covering from the upper 

* The method adopted by these writers for microscopical examination of the 
skin, was to take a piece of recent skin in which the vessels were distended by 
cadaveric accumulation of blood, or filled with injection. A portion from the heel 
is preferable. This is to be allowed partially to dry, and the thinnest possible 
transparent slice, cut off vertically. This is to be placed upon a piece of moist- 
ened glass and examined under the microscope with the use of a lamp and reflec- 
tor. In this way they were able readily to see, and isolate with curved cataract 
needles, all the vessels, nerves and glandular apparatus of the skin. — p. 

t From neuron, nerve, and thela, papilla. — p. 

I According to these writers the nerves, as they pass up from the under surface 
of the skin, become soft, flexuous, and capillary, and as they enter the villi on the 
top of the papilli, lose their neurilema, and are expanded in the form of pulp. They 
look upon the changes which the nerve undergoes, and upon the derm, villi, and 
epidermic covering, as so many parts necessary to constitute the perfect organ of 
touch : thereby assimilating it to the more complicated organs of sight and hear- 
ing. — Loc. cit. p. 1j, ct seq. — p. 

33* 



390 



STRUCTURE OF THE SKIN 



Fig. 29.* 




surface of the derm, and is there furnished with several layers of 
the epidermic horny matter, which 
cover it like a hood. This horny co- 
vering is particularly thick at the heel, 
and serves to protect the papillae by 
deadening shocks, and resisting the 
. pressure of the weight of the body. 
The papillae are most numerous on the 
palms of the hands and soles of the 
feet, but are also scattered in other 
parts of the body.f 

Of the Sudoriferous or Diapnogenous 
Apparatus. 

— This consists of a gland, see Fig. 28, p. 387, placed in the 
substance of the dermis, near its inner surface, into which a 
great many capillary vessels run, and of a spiral duct which runs 
up through the horny layer sand opens obliquely through the outer 
epidermic crust by a slight depression or pore, on the back of 
the epidermic ridges, formed over the papillary bodies. These 
are the orifices from which the sweat exudes, and may be readily 
seen with a single lens of moderate magnifying power, on the 
palms of the hands, soles of the feet, nose, and other portions of 
the body. The obliquity of the orifice, gives it a valvular ar- 
rangement, like that of the ureters where they enter the bladder. 
In consequence of this the valve closes the orifice, when the epi- 
dermis is raised by cantharides, and the duct is broken off, so that 
the pores are not generally visible, which has occasioned some 

* Fig. 29, represents the apparatus which constitutes the organ of touch in man. 
a, Nerve entering into the dermis, where it becomes capillary, b, Its entry into 
the papilla, c, Neurilema furnished by the dermis, d, Proper envelope of the 
nerve, e, Corneous layers more or less thick, which form the organ of protection 
to the nerve. The capillary blood-vessels which pass up with the nerves are not 
here shown. 

t From their observations upon the papillae of the whale, these anatomists are 
disposed to believe that the nervous fibrils terminate at the top of the villi, by loops 
with one another, as Prevost and Dumas have shown them to do in other parts of 
the body. — p. 



ACCORDING TO BRESCHET AND ROUSSEL DE VAUZEME 39 J 

anatomists, of great reputation, J. F. Meckel, Cruikshank, Blumen- 
bach, etc.* to deny altogether the porosity of the epidermis, and 
to believe that the sweat passed by exudation or exosmosis di- 
rectly through its substance. In carefully elevating the cuticle 
from the subjacent coats, these ducts are visible as very fine trans- 
parent elastic filaments ; the spiral being converted into straight 
tubes by the traction, and which W. Hunter, Bichat, and 
Chaussier, according to these writers, mistook for the exhalent 
and absorbent vessels.f Others supposed there were filaments 
of cellular tissue, uniting the epidermis to the subjacent layer.J 
The sudoriferous organs, which are exceedingly numerous, are 
probably the only exhaling organs of the skin. 

The Inhaling Apparatus. 

— This is properly an appendage of the absorbent system ; and 
may be seen, according to these anatomists, with a lens of 
feeble magnifying power, or even with the naked eye, in raising 
the epidermis with proper precaution. They have not, however, 
been enabled to make out their anatomy satisfactorily. They 
describe them, see Fig. 28, as arising by isolated radicles from 
the under surface of the grooves of the epidermis, and not open- 
ing to the surface ; the fluids which they take up getting into 
their cavities by previous imbibition through the outer cuticular 
covering. In passing downwards towards the derm, they are in 
company with the sudoriferous ducts, and in the substance of the 
derm, become continuous with the common absorbent vessels.§ 

* Beclard, was disposed to consider these pores as the orifices of the sebaceous 
glands, though he expresses himself doubtingly upon the subject, and says that 
the rout by which the sweat traverses the epidermis is entirely unknown. p. 

t The existence of exhalent vessels, was a mere presumption of Bichat, and has 
never been demonstrated. — p. 

t Eichhorn has also observed these sudoriferous canals, and his description of 
them corresponds in many respects with that of Breschet. Memoire sur les ex- 
halations que sc font par la peau, et sur la voies par lesquelles elles sont lieu ; par 
Henri Eichhorn. Arch, de Meckel. — p. 

§ The existence of these absorbent vessels immediately beneath the cuticle and 
on the upper surface of the dermis, has been demonstrated by Tiedemann, Fohman, 
and Lauth. Breschet asserts the discovery of an additional structure, in his in- 
haling apparatus, arising in the corneous tissue.— p. 



392 



STRUCTURE OF THE SKIN 



Fig. 30. 



Blennogenous Apparatus, 

— Or organs which, produce the mucous substance, which, in its 
first soft condition, forms the mucous body, heretofore known 
under the name of rete mucosum, and which, hardened upon the 
surface constitutes the horny matter of the epidermis. To see 
these well with the microscope, it is necessary to have a piece of 
fresh skin well injected with blood. There is then to be seen at 
the base of the derm, little reddish glands, irregular on the surface 
and grooved by blood-vessels. They are enveloped in cellular 
membrane and surrounded by a multitude of minute adipose 
vesicles. From the top of each of these glands as seen in Fig. 

30,* passes up a duct, 
which opens on the up- 
per surface of the derm 
d in the grooves between 

~~a the papilla. Many capil- 
lary vessels adhere to 
the tube and the gland, 
and a vessel of conside- 
rable size enters the base 
of the latter. The mu- 
cous matter thrown on 
the surface of the derm 
by these organs, quickly 
unites with a colouring 
matter, from which results the different tints of the corneous or 
epidermic substance, hair, nails, scales, feathers, etc., in man 
and other animals. This colouring is formed by the 




* Fig. 30. — Chromatogenous organ torn in two places, b and c, to show the escape 
of the scales, and the thread-like vessels of which this organ is composed, d, Its 
small excretory canals, torn in removing the corneous matter, e, Blennogenous or 
mucous gland, which throws its secretion above the chromatogenous organ./, Fluid 
state of the corneous matter, that is to say, pigmentum or scales floating in the 
midst of mucus, (rete mucosum of Malpighi.) g, Layers of corneous or horny 
matter stratified to the right and left, more and more condensed, the nearer they 
approach the surface. Into the mucous gland is seen running a sanguineous vessel, 
and round it are placed a number of little whitish granules. 



ACCORDING TO BRESCHET AND ROUSSEL DE VAUZEME. 393 

Chromatogenous* Apparatus, (See Fig. 30.) 

— Which is placed at right angles to the ducts of the mucous 
glands, at the upper surface of the derm, and at the bottom of 
the grooves. Its structure is parenchymatous or spongy. On 
its under surface, it receives a great number of minute capillary 
vessels, which is the outer limit of the vascular system, with the 
exception of the vessels which pass up into the villi. On its 
surface arises many short ducts, and which open in the grooves 
between the papillae, to convey up the colouring matter in the 
form of small granules to mix with the mucus. When this tissue 
is torn, a great many small filaments are seen (a,) from which es- 
cape small scales or colourless corpuscles in great quantities. 
(b, c.) This reservoir of scales is found in no other part of 
the derm. 

— At /, is seen the fluid state of the corneous matter, that is 
to say, the pigment of the scales floating in the midst of the 
mucus. At g, couches of this matter, hardened and stratified, to 
the right and left, as they approach the surface, and which form 
the coverings of the villi, and which is thus secreted and mould- 
ed around them. 

— The whole of the corneous tissue of the skin, (included usually 
under the terms of rete mucosum and epidermis,) is formed ac- 
cording to these anatomists of the mingled products of these 
mucous and colouring glands.f 

* From xpufx-jL, colour, and ytvvctu, to create. — p. 

t In investigating this obscure and difficult part of anatomy, it has been usual 
with observers to select the skin of the palms of the hands and soles of the feet» 
as a type of the whole cutaneous system. There is, however, a difference between 
them. In the palms and soles resides pre-eminently the sense of touch. These 
parts are likewise destitute of hair, and the papillae which are there very numerous 
and visible to the naked eye, are very sparsely distributed and appear rudimental 
in other parte of the body. Much of the discrepancy among anatomists in regard 
to the structure >f the skin, appears to be owing to whether they have made their 
researches mainly upon the palms and soles, or upon the skin of other parts of the 
body. Chevalier* and Wallace.t have described, especially in the skin of the 

* Lectures on the general structure of the human body, and on the anatomy and functions 
hi the skin, by J. Chevalier, 
t Lectures on the structure of the skin, by W. Wallace, London Lancet, 1837. 



394 0F THE CUTICLE. 

The Cuticula or Epidermis, 

Has been examined with the greatest care by several of the 
most successful anatomists; but notwithstanding their labours, 
the structure of this substance is by no means understood. 

It appears to have some resemblance to the matter of the 
nails, and of horn ; but is rather more flexible, even after allow- 
ing for the difference in thickness. 

In those parts where it is thinnest it is semitransparent. 

It is insensible, and no vessels can be seen in it.* 

It extends over the whole external surface of the body, except 
the parts covered by the nails, and is accommodated to the sur- 
face of the skin, by forming ridges or furrows, corresponding 
to it. 

It adheres most closely to the cutis ; and when abraded by 
mechanical violence, the surface of the skin appears moistened 
by effusion. 

It is not certain that its mode of union with the skin is per- 
fectly understood ; the adhesion of these membranes to each 
other is as uniform as that of two smooth surfaces glued together, 
but it is generally said that the cuticle is attached to the cutis by 
very numerous and fine filaments. 

It has often been asserted that these filaments are the exhal- 
ing and absorbing vessels, which pass through the cuticle, to and 

face, arms and legs, a system of epidermoid glands, seated in the rete mucosum, 
and so minute that the latter counted one hundred of them in the i^h part of a 
square inch, and which gives issue to the sweat. These appear to me, to corre- 
spond with the diapnogenous apparatus of Breschet, as he represents them in the 
palms and soles. 

This opinion of Bichat, is therefore erroneous, viz. that the sense of touch is 
only more perfect in the hands than other parts, in consequence of the shape of 
the parts, and the facility with which they may be applied round objects, and that 
the skin of the abdomen substituted for that of the fingers, would have constituted 
organs of touch. — p. 

* In the early part of the last century, an anatomist by the name of St. Andre, 
exhibited a preparation of the cuticle which appeared to be injected with mercury. 
Ruysh declared the thing impossible, and invited him to an investigation of the 
subject. This invitation was not accepted, and the affair has been generally con- 
sidered as a mistake or an imposition. — h. 



OP THE CUTICLE. 395 

from the skin. This sentiment appears very reasonable, but no 
vessels that pass in this way can be injected. 

There are innumerable processes which pass from the cuticle 
to the skin. Many of these are the linings of the cavities which 
contain the roots of the hairs ; but they are reported by micro- 
scopical observers to be like the ringers of a glove, closed at 
their extremities. 

There are also many processes which contain a sebaceous 
substance that may be pressed out of them in the form of worms: 
these are the ducts of sebaceous glands. 

Besides these, there is an immense number of whitish filaments, 
which are as fine as the most delicate thread of a spider's web. 
These filaments can be best seen while the cuticle is separating 
from the skin of the sole of the foot, as suggested by Dr. Wil- 
liam Hunter.* They are supposed to be vascular, but they have 
never been injected. 

When the cuticle is in its naturul situation, in union with the 
skin, there appears to be three species of foramina or pores, on 
its external surface: viz. 1. Those formed by the passage of 
the hairs ; and 2. Those which are the orifices of the ducts of 
the sebaceous glands ; each of which has been already mentioned. 
And 3. Such pores, as exist on the ends of the fingers and the 
inside of the hands. 

It is said that these last are very visible, when magnified to 
twice or thrice their original bulk, and drawings of them have 
accordingly been made by Dr. Grewf and by Mr. Cruikshank.J 
Small specks of fluid can be seen with the naked eye, in the same 
situations, in warm weather, or when the ends of the fingers are 
made turgid by a ligature. It is probable that they are formed 
by the accumulation of fluid at these orifices. 

The above described pores are situated on the ridges at the 
ends of the fingers and not in the furrows; and it is prcbable that 
similar pores are distributed over the surface of the body. 

Notwithstanding the appearance of these foramina, when the 

» See the London Medical Observations and Inquiries, vol. ii. — h. 

+ In the Philosophical Transactions, vol. iii. Lowthrop's Abridgement. 

t Sec his Experiments on Insensible Perspiration. 



396 0F THE CUTICLE. 

cuticle is in its natural situation, several of the most successful 
investigators of the subject have declared that they could not 
discover any pores or foramina in the cuticle, when it was sepa- 
rated from the cutis. 

The late Professor Meckel of Berlin, who was one of this 
number, was induced to believe that the matter of exhalation, and 
of absorption, soaked through the cuticle, as the vapour of warm 
water passes through leather.* 

In support of this doctrine he states that perspiration goes on 
through the cuticle on the palms of the hands and soles of the feet 
when it is very thick ; and observes, that if it were transmitted 
by delicate vessels, the vessels in the feet must be torn by the 
weight of the body, in persons who walk; and those in the hands 
would experience the same fate, in labourers, who work with 
heavy hammers, &c. 

On the other hand, Mr. Cruikshank, who could likewise find 
no pores in the separated cuticle, contends strenuously for their 
existence notwithstanding; and explains their non-appearance by 
the following facts, among others, viz. that no foramen will ap- 
pear in the separated cuticle, although it has been punctured by 
a needle; and that when the cuticle has been peeled off, from 
portions of the cutis on which were hairs which must necessa- 
rily have perforated it, no foramina have appeared in it. 

M. Bichat took very different ground : he asserted that the 
pores of the separated cuticle were to be seen distinctly, in large 
numbers, by looking through it towards the light ; he also be- 
lieved that the course of the exhalent vessels, through the cuticle, 
might be seen in the same manner ; and that they passed ob- 
liquely. 

That the cuticle is pervious, is proved incontestably by the 
functions of perspiration and sweating, as well as of absorption ; 
but there are good reasons for believing that the perforations of 
the cuticle have a peculiar structure ; and are not simple fora- 
mina. Thus, when a vesicle is formed by the operation of can- 
tharides or any other process, if the cuticle is not lacerated, it 

* See Memoirs of the Royal Academy of Sciences of Berlin, vol. xiii. for 1757. 



CAUSES WHICH PRODUCE VESICATION. 397 

will confine the effused fluid for a considerable time, without any 
appearance of its escape through these pores. 

This fact, which is strongly opposed to the hypothesis of 
Meckel, is explained by Cruikshank upon the supposition that 
the pores of the skin are lined by processes of the cuticle, and 
that when the cuticle is separated from the cutis, these processes 
go with it, and act like valves in confining the fluid. 

Bichat supposes the oblique vessels to produce the same effect 
upon analogous principles ; and compares their situation to that 
of the ureters, which pass obliquely between the coats of the 
bladder. 

This peculiar quality of the cuticle, in admitting of perspira- 
tion and sweat, and also absorption, while it prevents evapora- 
tion from the parts which it encloses, is of immense importance. 

If a portion of skin be deprived of cuticle a short time before 
death, by a blister for example, this portion will, in a few days, 
become perfectly dry and hard, like horn ; while the other parts 
of the skin of the subject, covered by the cuticle, retain their 
moisture and flexibility. 

It may, therefore, be admitted, that the use of the cuticle is to 
keep the skin soft and flexible, by confining its moisture, as well 
as to defend it.* And it is probable that the sebaceous matter 
is secreted for the purpose of preserving the cuticle in a state of 
flexibility. 

As the cuticle is capable of confining fluid, and resisting the 
action of chemical agents, it is surprising that epispastics and 
rubefacients should act through it, upon the skin, with so much 
certainty as we find they do ; and that cantharides should pro- 
duce vesications, when applied dry. 

The thickness of the cuticle on every part of the body is much 
increased by long continued pressure, forming corns and excres- 
cences of its own nature. By this cause also it is rendered 
very thick on the palms of the hands and soles of the feet ; 
although it is originally thicker there than in other parts. 

* This property of the cuticle is rendered very apparent in attempting to dry 
anatomical preparations with the skin on, in which the student will fail, unless the 
cuticle is previously removed by maceration. — r. 

vol. i. 34 



398 SEPARATION OF THE CUTICLE. 

It is said that, after long boiling, these thick portions of cuticle 
may be separated into distinct lamina. 

In the living subject, the cuticle, when immersed in warm 
water, seems to absorb some of that fluid ; as is evinced by the 
hands when they have been long in that situation ; and also by 
those parts of the skin to which poultices have been applied. 

Notwithstanding the uniform adhesion of the cuticle to the 
cutis, it is observed, in the living subject, to be separated, and 
formed into vesicles, by a variety of causes, viz. 

1. Pinching of the skin, or violent mechanical irritation; such 
as labouring with hard instruments. 

2. By the application of cantharides, and certain other sub- 
stances which produce vesications. Sometimes these substances 
appear to inflame the skin ; but on other occasions the vesica- 
tion is produced while the skin appears unchanged in colour, 
and free from inflammation. The process appears different from 
that of simple inflammation ; for certain rubefacients often in- 
flame the skin considerably without vesicating or blistering it. 

3. The boiling heat will, very generally, produce vesication. 

4. Certain diseased processes seem to occasion vesication in 
a manner which is not well understood, viz. erysipelas, zona, or 
shingles, pemphigus, and some other eruptions which have no 
name. In erysipelas there is an obvious inflammation of the 
skin ; but in some of the other diseases the vesication takes place 
without the appearance of inflammation. 

5. Vesications often appear when there is a tendency to gan- 
grene. 

6. They also occur in some cases of simple fracture, where 
there is considerable injury. In these cases the fluid effused is 
often tinged with blood. 

After death the cuticle is separated from the cutis : 

1. By putrefaction ; in which case large vesicles are some- 
times formed. 

2. By long continued maceration. 

3. By boiling, and 

4. By violent dry heat. 

The cuticle appears to be least deranged when it is separated 



CHEMICAL QUALITIES OF THE CUTICLE. 399 

by putrefaction and maceration : in these cases the internal sur- 
face corresponds to the surface of the skin ; and the processes 
which contain the hairs, as well as those which are the ducts of 
the sebaceous glands, are particularly obvious. 

The external surface of the cuticle varies in different places, 
according to the surface of the skin. In some places it appears 
scaly at times, and has therefore been supposed to consist entirely 
of scales; but in other parts, when examined attentively, it ap- 
pears like a half transparent concreted substance, with a rough 
surface. 

When the skin has continued dry for a long time, bran-like 
scales can be rubbed off from it. These are probably composed 
of the residuum of the secretion deposited on the skin, and of a 
portion of the external surface of the cuticle. The same sub- 
stance appears upon the first washing of the skin, after that pro- 
cess has been discontinued for any length of time. 

Many speculations have arisen respecting the manner in which 
the cuticle is originally formed, and reproduced ; but none of 
these are perfectly satisfactory. 

It is also a question whether the cuticle is endued with vitality, 
or is merely an inanimate unorganised concrete. No decisive 
argument have been adduced in favour of its vitality; and it 
has already been stated, that neither nerves nor vessels can be 
demonstrated in it. 

It appears particularly calculated for protecting the skin which 
it covers ; for it is insoluble in water, and resists the action of 
several powerful chemical agents. Thus, it is not affected by 
immersion for a considerable time in the sulphuric and muriatic 
acids ; although the nitric acid acts upon it. 

Jt resists for a short time, but is at length dissolved, by the 
pure fixed alkalies, and by lime. 

It is supposed by the chemists to consist of albumen, in a pecu- 
liar state of modification. 

— Malpighi, was the first to discover, by the use of the mi- 
croscope, an intervening substance between the cuticular cover- 
ing, and the cutis vera, which he called the rete mucosum or 
corpus reticuJare. This he considered the seat of coloration in 



400 CHEMICAL QUALITIES OF THE CUTICLE. 

the negro, and asserted the cuticle to be alike in all varieties of 
the human race, that is, colourless. For a long period his re- 
searches formed the basis of all the systematic treatises upon the 
skin, and it is only within a recent period, as has before been ob- 
served, that the study of the subject has been resumed. 
— The cuticle of the black is now, generally admitted to be of 
an ashy colour.* And Flourensf has shown, that the reticular 
appearance of the rete mucosum is entirely an adventitious cir- 
cumstance. Malpighi first discovered his rete mucosum on the 
tongue of the ox, and subsequently under the epidermis of the 
human hand, and from which he drew his description. By ebul- 
lition he softened the outer covering of the cutis vera, and then 
tearing off the epidermis, he saw a layer of soft substance with 
holes in it like the meshes of a net. This was owing to a lacera- 
tion of the mucous layer : the part covering the apices of the villi 
going off with the cuticle, while that between the villi and the 
bases of the papillae adhered to the cutis vera. By maceration 
in water, which is the surest and most successful method of ef- 
fecting a dissection in delicate parts, Flourens, found in the same 
organs, the cuticle to come off, leaving the whole of the mucous 
body attached, which then presented none of the reticular appear- 
ance. The cuticle and mucous body were both continuous lay- 
ers, covering the papillse and forming their sheaths. The sheaths 
formed by the latter body were broken in Malpighi's preparation. 
— The cuticular sheaths in the ox, were thin and delicate over 

* Breschet has asserted that the colour of the skin in different animals is depen- 
dent upon the form of the scales of the epidermis, by which the light is reflected. 
The larger cut represents, after this observer, the 
scales of the epidermic or corneous matter of a white &' 

man, diluted witli water, and highly magnified, in 
which are seen fragments of the sudoriferous canals 
and inhalent vessels. The scales all have a trape- 
zoidal or lozenge shape. The smaller cut, represents 
a single scale from the skin of a whale, highly mag. 
nified. It is black at its .summit, and whitish at its 
pedicle of insertion. The skin of the whale is black, and these writers assert, that 
in all animals with black skins, including negroes, the scales of the epidermis, 
appear under the microscope of this shape or spatulate. — p. 

f Annales des sciences naturelles, 1837.— p. 




THE NAILS. 401 

the fungiform or smaller papillae, but formed thick horny layers 
over the larger which assist in the action of mastication. 
— Albinus, repeating the experiments of Malpighi, corrected his 
error, and in the beautiful designs of Ladmiral, has represented 
the mucous body as a continuous layer. Since then by Bichat 
and others, the use of the term rete mucosum, has been con- 
tinued, not exactly in the original signification of Malpighi, but 
under the belief that it contained a net-work of vessels. Its 
foliated structure has been well established by Cruikshank, Gaul- 
tier, and Flourens. It thus appears that the whole of the anato- 
my of the skin, requires to be constructed anew. Several of 
the German and French anatomists have applied themselves to 
the task, among whom may especially be mentioned, Weber* 
of Leipzig, and Breschet of Paris.f The views of the latter, on 
account of his having treated the subject more extensively than 
the rest, as well as from his high situation in the school of Paris, 
have already been given. — 

The JVails. 

The roots of the nails appear to originate in a fold of the 
cutis vera, from the epidermis which lines the fold ; but the bo- 
dies of the nails adhere firmly to the cutis on which they lie, 
and appear to cover it, in the place of the cuticle. The papillae 
of those parts of the cutis which are covered by the nails are 
very conspicuous when the nails are removed. It has been sup- 
posed that there was no rete mucosum between the nails and 
cutis ; but this opinion is probably erroneous, as the black pig- 
ment is perceptible under the nails of some negroes. 

The nails can be separated from the cutis by all those pro- 
cesses which separate the cuticle from it. When this is effected, 
they remain connected with the cuticle, which appears to be 
continued into them ; and on this account, as well as their insen- 
sibility, and their resemblance to the horny excrescences of the 
cuticle, they are considered as appendages of it. 

* Arch, fur die Physiologic — p. 

t Nouvelles Recherches sur la Structure de la Peau, par G. W. Breschet et 
itoussel de Vauzemc. Paris, 1835. — p. 

44* 



402 



GROWTH OF THE NAILS. 



The root is opaque, and appears white. The body is trans- 
parent, and in health shows the florid colour of the cutis which 
it covers ; but the colour of this portion of the cutis depends 
upon the state of the circulation ; and becomes livid when the 
blood is disoxygenated, or when the circulation ceases there ; 
and this colour also appears through the nails. 

The nails are unquestionably organised, although their ulti- 
mate structure is not known. They appear to be composed of 
lamellae, and these lamellae of fibres. They grow rapidly, and 
w r hen they are not pared or worn away, they sometimes acquire 
an immense size. 

As a remarkable instance of this, it is related, that a nail of 
the great toe was sent from Turin to the Academy of Sciences 
at Paris, which measured four inches and a half in length. 

The growth seems to take place altogether at the roots. 

The nails, when chemically examined, appear to consist of a 
modification of albumen ; and thus resemble cuticle and horn in 
their composition. 

— The growth of the nails, forwards, is entirely from a fold 
of the cutis vera, at its root, called, though not with exact pro- 



Fig. 32. 




prietv, the matrix of the nail, as seen 
in Fig. 32. It grows also in thickness 
from the upper surface of the skin, 
upon which the nail rests. In the 
formation of a new nail the lamen 
which starts from the matrix, receives 
successive layers, as it approaches the 
extremity, the deepest seated of which is the shortest. In this 
way the nail gets its thickness and strength, and occasionally, 
where the deposition of new matter, goes on more rapidly under 
the body of the nail than at the matrix, the body is thrown up into 
unsightly rugosities. Its developement is exactly similar to that 
of the horns and hoofs of animals. The striated appearances of 
the nail, is said to be owing to the papillary prominences below. 
The white semicircular line at the root, is called the lunula. 
— The nails are not exactly analogous in structure to the cuticle, 
in the ordinary acceptation of the term, to that part which is 
raised up under a blister. The proper cuticle is that thin coatm? 



THE HAIRS. 403 

which is scraped away and worn off near the root, and which 
otherwise would cover the surface. The nails consist of the pro- 
per cuticle, and tunica albuginea superflcialis and gemmules of 
Gaultier — leaving interposed between them and the cutis vera, the 
tunica albuginea profunda which is insensible, and explains why 
it is that a splinter, or the blade of a small pair of scissors, in 
the operation for onychia, may be run along close on the under 
surface of the nail, without the production of much pain. Ac- 
cording to Breschet, the nail is formed like the other parts of the 
horny coat exterior to the cutis vera, by the glands for the se- 
cretion of the mucus and colouring matter; the products of 
which would be mixed up together, colouring the substance of 
the nail, as we know is the case in regard to the horns and hoofs 
of animals. — 

The Hairs 

Originate from bulbs which are situated at the bottom of pores 
or cavities in the skin. These pores appear to be lined by a 
production of the cuticle, and the extremities of the bulbs project 
beyond them into the cellular membrane. In some cases, where 
the cuticle is separated after putrefaction, it seems that these 
lining processes of the cuticle come away completely, and bring 
the hairs and the roots with them ; but in other cases, the cuticle 
separates from the cutis, and leaves the hairs in their natural 
situation.* 

When viewed in a microscope, the bulb appears half trans- 
parent, and whitish; and of a softer consistence than the hair 
itself. The extremity of it is remarkably flexible, and sometimes 
much darker than the rest of the bulb. The hair does not appear 
to extend completely to the end of the bulb. Neither blood- 
vessels nor nerves have been traced to these bulbs, although it is 
probable they extend there : for the operation of extracting hair 

* Dr. Dom. Nardo, of Padua, asserts that he has succeeded frequently upon him- 
self, in transplanting a hair with its bulb, from one of the pores of the head into one 
of the pores of the chest ; which is done by enlarging the latter pore with a needle, 
introducing the bulb into it with exactness, and exciting a slight inflammation 
around it by friction. The planted hair takes root, grows, and in process of time, 
undergoes the usual changes,— becomes gray, and is shed.— Giorn delV Ital.—v. 



404 BULBS OF THE HAIRS. 

by the roots is generally very painful ; and blood sometimes ap- 
pears in the pore from which the hair is extracted. 

The body of the hair appears to be composed of smaller 
fibres, enclosed in a membrane which often is imperfect at the 
extremity; in consequence of which the fibres often separate 
from each other, or split. 

Within the hair is diffused the substance upon which its colour 
depends : this does not appear to be essential to the structure, as 
in the advance of life the hair is so generally without it, while 
its structure continues unchanged, although it becomes less 
flexible. 

The colour of the hair appears to have some connexion with 
the colour of the rete mucosum, as it is so generally black when 
the rete mucosum is dark coloured. 

The sudden change of colour in consequence of fright or grief, 
is a very rare occurrence indeed ; but Bichat relates an instance 
which came under his observation, in which the hair became 
perfectly white in one night, in consequence of grief. 

— The substance of the hair is of a corneous nature like the epi- 
dermis. Each hair consists of two parts, a bulb or follicle, and 
a stalk or hair proper. 

— The follicle is ovoidal, and consists of two membranes. The 
exterior is white, firm, and continuous with the cutis vera ; the 
interior, which is thin soft and reddish, appears to be continuous 
with the rete mucosum. 

— The cavity of the follicle is filled up at the bottom with a coni- 
cal papilla, into which, according to Beclard, the nerves and 
blood-vessels may be seen running below. Rudolphi and An- 
dral, have traced the nerves into the whiskers of the seal ; Shaw 
has done the same, and discovered that they were branches of 
the fifth pair. The root of the hair possesses a conical cavity, 
in which is lodged the point of the papilla which appears 
to secrete the matter of the hair, and cause its growth, by the 
continuous deposition of new matter at its root, as takes place in 
regard to the nails of man, and the horns of animals; this de- 
posit of new matter in the fluid state, has been seen between the 
hair and papilla. It is sometimes secreted in profusion, espe- 



STRUCTURE OF THE HAIRS. 405 

cially in the head ; and has appeared to me, by overflowing from 
the follicles, and drying in the form of scales, to be the source of 
the dandruff. 

— The epidermis is reflected from the mouth of the follicle, and 
lost upon the surface of the hair. 

— The hair, when examined with the microscope, appears to be 
covered externally with small scales, and to be hollow internally. 
The latter, however, appears to be in the human hair, an optical 
illusion. The stalks of hairs have neither vessels nor nerves in 
their structure, and anatomists no longer admit a fluid in their 
interior described by Bichat and others as the marrow.* 
— Around the orifices of the follicle, and in the substance of its 
neck according to Gaultier, we find a number of minute seba- 
ceous glands, that secrete an unctuous fluid, which imbues the 
hair and preserves its softness and pliability. The hairs are'hy- 
grometrical, and increase in length and thickness when exposed 
to humidity ; and are shortened again by dry heat. 
— From the changes which take place in regard to the colour 
of the hair, there is reason to believe, that it is traversed by some 
fluid. This passes along the hair by imbibition, from the root up- 
wards, in consequence of its hygrometrical nature, passing up 
through the spongy tissue of which the body of the hair appears 
to me to be formed. This fluid is derived from the surface of 
the skin forming the papilla, and is analogous to the fluid of the 
rete mucosum, and corresponds more or less in colour with that 
of the skin and iris. 

— The hairs vary much in size, but appear all to be constructed 
on the same plan. They have different names in different parts 
of the body, as beard, whiskers, eyelashes, &c. The minute 
hairs generally spread over the body, are called down or du- 
vette, and those which cover the scalp, in man, have particu- 
larly appropriated to them the term of hair. In the white or 
Caucasian variety of the human race, the hairs of the head are 
very numerous, fine, long, and vary in colour from white to 
black: in the Mongolian they are straight, black and short: in 

* Note to Bichat, 4th edit. Paris.— p. 



406 CHEMICAL COMPOSITION 

the Negro, black, fine, thick and crisped : in the Indian, black, 
straight fine and thick : and in the Malay, thick and frizzled. 
— Their size and number vary in regard to their colour. Withoff, 
has calculated that in a square inch of skin there are one hun- 
dred and forty-seven black hairs, one hundred and sixty-two, 
chesnut, and one hundred and eighty-two, blond. 
— The hairs are composed chemically, agreeably to Vauquelin. 
chiefly of animal matter, of some concrete white, and some black 
oily matter ; iron, oxide of manganese, phosphate and carbonate 
of lime, silex and sulphur. The change of colour to gray, is 
said to be owing to a preponderance in the formation of the 
white oily substance, and the developement of some phosphate 
of magnesia.* The shape of the hairs vary in different parts. 
— From the large size of the nerves which enter the papillae, to 
which the hairs are attached, .they become in many animals 
delicate instruments of touch. The formation of the hair de- 
pends upon the follicle ; while this remains healthy, though the 
hair should be removed by its roots, it will again be reproduced. 
— Boucheron in a recent work on the hair, says that in baldness 
the bulbs are often only partially atrophied, a circumstance which 
does not render hopeless the idea of their recovering their origi- 
nal functions, and re-secreting the horny matter which forms the 
hair, under the influence of certain stimuli. 
— Round the bulbs of the larger hairs, are found some smaller 
ones, which, as seen in extraction of the former in some cases of 
tinea capitis, are sometimes developed to an unusual extent. 
— It has also been frequently observed, that in many women the 
almost imperceptible down of the face presents, after the fortieth 
or fiftieth year of age, a great increase of developement. 
— The bulbs of the hairs are obliquely and confusedly implanted 
in the dermis — hence when one straggling white hair, is extract- 
ed from the head, the neighbouring ones speedily whiten in their 
turn from the disturbance and injury which their bulbs have 
suffered. 
— There are many hairs, which are developed so feebly that they 

* C. P. Ollivier. 



OF THE HAIRS. 407 

do not pass the epidermis, but roll and curve themselves under it. 
From accidental circumstances the energy of the bulbs of these 
hairs is sometimes so increased, that skin which had been pre- 
viously smooth, becomes hairy. Boucheron, attributes the colour 
of the hair to a peculiar animal oil, secreted by the bulbs, and 
varying consequently in its properties in different individuals. 
It is to a change in the colour of this oily matter, arising from a 
variety of causes, which enfeeble the general system, as grief, in- 
tense study, &c, that is attributed the whitening of the hair. — 

The skin, constructed as above described, answers a fourfold purpose in 
the animal economy. It is the organ of touch. It covers and protects the 
whole structure. It is the outlet for a large proportion of the insensible 
perspiration, and it performs absorption. 

Many facts have been noticed by practitioners of medicine, which prove that 
it has a connexion with the lungs and stomach, which is not yet explained 
by anatomy. 

\s one of these, an effect of the urticaria or nettle-rash may be mentioned. 
This eruption sometimes relieves completely the spasmodic croup ; and in 
other cases, nausea and vomiting. 

Some children, when affected with this species of croup, are relieved by rub- 
bing the skin with harsh woollen cloth. 

In some places, the urticaria and the affection of respiration are so much re- 
garded as symptoms of the same disease, that the terra hives is used as the 
name for each of them. 



PART V. 

OP THE NOSE, THE MOUTH, AND THE THROAT. 
CHAPTER XII. 

OF THE NOSE. 

The prominent part of the face, to which the word nose is ex- 
clusively applied in ordinary language, is the anterior covering 
of two cavities which contain the organ of smelling. 

These cavities are formed principally by the upper maxillary 
and palate bones; and, therefore, to acquire a complete idea of 
them, it is necessary to study these bones, as well as the os eth- 
moides, the vomer, and the ossa spongiosa inferiora, which are 
likewise concerned in their formation. 

In addition to the description of these bones, in the account of 
the bones of the head, it will be useful to study the description 
of the cavities of the nose which follows it, (see page 108.) 

After thus acquiring a knowledge of the bony structure, the 
student will be prepared for a description of the softer parts. 

Of the External Nose. 

The superior part of the nose is formed by the ossa nasi, and 
the nasal processes of the upper maxillary bones, which have 
been already described, (see pages 77-80); but the inferior 
part, which is composed principal^ of cartilages, is much more 
complex in its structure. 

The orifice, formed by the upper maxillary and nasal bones, 
is divided by a cartilaginous plate, which is the anterior and in- 
ferior part of the septum, or partition between the two cavities 
of the nose. The anterior edge of this plate projects beyond the 
orifice in the bones, and continues in the direction of the suture 



OF THE NOSE. 



409 



between the ossa nasi. This edge forms an angle with the lower 
edge of the same cartilage, which continues from it in a hori- 
zontal direction, until it reaches the lower part of the orifice of 
the nose, at the junction of the palatine processes of the upper 
maxillary bones ; where a bony prominence is formed, to which 
it is firmly united. The upper part of the anterior edge of this 
cartilage, which is in contact with the ossa nasi, is flat, and is 
continued into two lateral portions that are extended from it one 
on each side, and form a part of the nose : these lateral portions 
are sometimes spoken of as distinct cartilages, (superior lateral,) 
but they are really continuations of the middle portion or septum. 

Below the lower edge of these lateral portions are situated 
the cartilages which form the orifices of the nose, or the nostrils. 
Of these, there is one of considerable size, (inferior lateral,) and 
several small fragments, on each side of the septum. Each of 
the larger cartilages forms a portion 
of an oval ring, which is placed ob- 
liquely on the side of the septum : 
so that the extremity of the oval points 
downward and forward, while the 
middle part of the oval is directed up- 
wards and backwards. The sides 
of this cartilage are flat, and unequal 
in breadth. The narrowest side is in- 
ternal, and projects lower down than 
the cartilaginous septum; so that it is 
applied to its fellow of the other nostril. 
The external side is broader, and con- 
tinues backward and upward to a con- 
siderable distance. 

The upper and posterior part of this oval ring is deficient; but 




* Fig. 33. — a, b, Ossa nasi, which show above, the serrated surface by which they 
are united to the os frontis. c, d, Superior lateral cartilage, e, Vertical cartilagi- 
nous septum of the nose. /, /, Sesamoid cartilages, filling up part of the vacuity 
here, g, I, Oval cartilages, or cartilages of the alae nasi, h, i, k, Small square carti- 
lages appended to the alse nasi and circumscribing the outer and back part of the 
nostrils, m, n, o, Same parts of the right side. 

vol. i. 35 



410 0F THE NOSE. 

the remainder of the nostril consists of several small pieces of 
cartilage, {curtilages carres,) which are fixed in a ligamentous 
membrane that is connected by each of its extremities to the 
oval cartilage, and thus completes the orifice. 

The anterior parts of the oval cartilage form the point of the 
nose ; and the ligamentous portions, the alas or lateral parts of 
the nostrils. 

When the external integuments and muscles are removed 
from the lower portion of the nose, so that the internal mem- 
brane and these cartilages only remain, the internal membrane 
will be found attached to the whole bony margin of each orifice, 
and to each side of the whole anterior edge of the middle carti- 
lage, which projects beyond the bones. This membrane is after- 
wards continued so as to line the oval cartilages and the elastic 
membrane of the ala nasi, to the margin of the orifice of the 
nostril. 

The internal portions of the oval cartilages being situated 
without the septum, and applied to each other, they form the ex- 
ternal edge of the partition between the nostrils, or the columna 
nasi ; which is very movable upon the edge of the middle car- 
tilage. 

The orifices of the nostrils, thus constructed, are dilated by 
that portion of the muscle, called Levator Labii Superioris Alee- 
que Nasi, which is inserted into the alas nasi. 

They are drawn down by the depressor labii superioris 
alaeque nasi. They are pressed against the septum and the 
nose by the muscle called Compressor JVaris, which has however 
an opposite effect when its upper extremity is drawn upwards by 
those fibres of the occipito-frontalis, which descend upon the 
nose, and are in contact with it. 

The end of the nose is also occasionally drawn down, by 
some muscular fibres which descend from it, on the septum of 
the nose, to the orbicularis oris : they are considered as a por- 
tion of this muscle by many anatomists, but were described by 
Albinus as a separate muscle, and called JVasalis Labii Supe- 
rioris. 

When inspiration takes place with great force, the alas nasi 



OF THE CAVITIES OF THE NOSE. 4 J 1 

would be pressed against the septum, if they were not drawn 
out and dilated by some of the muscles above mentioned. 

Of the Cavities of the Nose. 

To the description of the osseous parts of the nasal cavities in 
page 80, it ought now to be added, that the vacuity in the 
anterior part of the osseous septum is filled up by a cartilaginous 
plate, connected with the nasal lamella of the ethmoid bone 
above, and with the vomer below. This plate sends off those 
lateral portions already described, which form the cartilaginous 
part of the bridge of the nose. 

It should also be observed that at the back parts of these 
cavities are two orifices called the Posterior JVares, (see Fig. 34, 
p. 417,) which are formed by the palate bones, the vomer, and 
the body of the sphenoidal bone, and are somewhat oval. 

The nasal cavities, thus constructed, are lined by a peculiar 
membrane, which is called pituitary from its secretion of 
mucus, or Schneiderian after an anatomist who described it with 
accuracy.* 

This membrane is very thick and strong, and abounds with so 
many blood-vessels, that in the living subject it is of a red colour. 
It adheres to the bones and septum of the nose like the perios- 
teum, but separates from them more easily. The surface which 
adheres to the bones has some resemblance to periosteum, while 
the other surface is soft, spongy, and rather villous. Bichat 
seems to have considered this membrane as formed of two 
lamina, viz. periosteum, and the proper mucous membrane; but 
he adds, that it is almost impossible to separate them. 

It has been supposed that many distinct glandular bodies were 
to be seen in the structure of this membrane by examining the 
surface next to the bones ;f but this opinion is adopted by verv 
few of the anatomists of the present day. The texture of the 
membrane appears to be uniform ; and on its surface are a great 

* Conrad Schneider, a German professor, in a large work, " De Catarrhis," 
published about 1660. 
t See Winslow, Section X. No. 337. 



412 SCHNEIDERIAN MEMBRANE. 

number of follicles of various sizes, from which flows the mucus 
of the nose. 

These follicles appear like pits, made by pushing a pin ob- 
liquely into a surface which retains the form of the impression. 
They can be seen very distinctly with a common magnifying 
glass when the membrane is immersed in water, both on the 
septum and on the opposite surface. They are scattered over 
the membrane without order or regularity, except that in a few 
places they occur so as to form lines of various lengths, from 
half an inch to an inch. The largest of them are in the lower 
parts of the cavities. 

It may be presumed that the secretion of mucus is effected 
here by vessels which are mere continuations of arteries spread 
upon a surface analogous to the exhalents, and not convoluted in 
circumscribed masses, as in the case of ordinary glands. 

The arteries of this membrane are derived from various 
sources : the most important of them is the nasal branch of the 
internal maxillary, which passes into the nose through the sphe- 
nopalatine foramen, and is therefore called the Spheno-palatine 
Artery. It divides into several twigs, which are spent upon the 
different parts of the surface of the nasal cavities. Two of them 
are generally found on the septum of the nose: one, which is 
small, passes forwards near the middle; the other, which is 
much larger, is near the lower part of it. 

Two small arteries, called the anterior and posterior ethmoi- 
dals, which are branches of the ophthalmic, enter the nose by 
foramina of the cribriform plate of the ethmoidal bone. These 
arteries pass from the orbit to the cavity of the cranium, and 
then through the cribriform plate to the nose. In addition to 
these, there are some small arteries derived from the infra-orbi- 
tal, the alveolar and the palatine, which extend to the Schneide- 
rian membrane; but they are not of much importance. 

The veins of the nose correspond with the arteries. Those 
which accompany the ethmoidal arteries open into the ocular 
vein of the orbit, which terminates in the cavernous sinuses of 
the head. The other veins ultimately terminate in the external 
jugulars. 



OLFACTORY NERVES. 413 

The nerves of the nose form an important part of the structure; 
they are derived from several sources; but the most important 
branches are those of the olfactory. 

The olfactory nerves form oblong bulbs, which lie on each 
side of the crista galli, on the depressed portions of the cribri- 
form plate of the ethmoid bone, within the dura mater. These 
bulbs are of a soft consistence, and resemble the cortical part of 
the brain mixed with streaks of medullary matter. They send 
off numerous filaments, which pass through the foramina of the 
ethmoid bone, and receive a coat from the dura mater as they 
pass through it. 

These filaments are so arranged that they form two rows, 
one running near to the septum, and the other to the surface of 
the cellular part of the ethmoid bone, and the os turbinatum : 
and in addition to these are some intermediate filaments. 

When the Schneiderian membrane is peeled from the bones to 
which it is attached, these nervous filaments are seen passing 
from the foramina of the ethmoid bone to the attached surfaces: 
one row passing upon that which covered the septum, and the 
other to that of the opposite side; while the intermediate fila- 
ments take an anterior direction, but unite to the membrane as 
soon as they come in contact with it. 

All of these can be traced downwards on the aforesaid sur- 
faces of the membrane for a considerable distance, when they 
gradually sink into the substance of the membrane, and most 
probably terminate on the internal villous surface ; but they have 
not been traced to their ultimate termination. They ramify so 
that the branches form very acute angles with each other. On 
the septum the different branches are arranged so as to form 
brushes, which lie in contact with each other. On the opposite 
sides, the different ramifications unite, so as to form a plexus. 

Dr. Soemmering has published some very elegant engravings 
of the nose, representing one of his dissections, which appears 
to have been uncommonly minute and successful.* These re- 
present the ramifications as becoming more expanded and deli- 

* They are entitled, Icoaes Organorum Humanorum Olfactus. 
35* 



414 SPHENOPALATINE AND OTHER NERVES OF THE NOSE. 

cate in the progress towards their terminations, and as observing 
a tortuous course, with very short meandering flexures. 

It is to be observed that the ramifications of the olfactory 
nerve, thus arranged, do not extend to the bottom of the cavity. 
On the external side, they are not traced lower than the lower 
edge of the ethmoid, or of the superior spongy bone : and on 
the septum, they do not extend to the bottom, although they are 
lower than the opposite side. On the parts of the membrane not 
occupied by the branches of the olfactory nerves, several other 
nerves can be traced. The nasal twig of the ophthalmic branch 
of the fifth pair, after passing from the orbit into the cavity of 
the cranium, proceeds to the nasal cavity on each side by a 
foramen of the cribriform plate ; and after sending off some 
fibrillee, descends upon the anterior part of the septum to the 
point of the nose. The spheno-palatine nerve, which is derived 
from the second branch of the fifth pair, and enters the nose by 
the spheno-palatine foramen, is spread upon the lower part of the 
septum and of the opposite side of the nose also, and transmits a 
branch through a canal in the foramen incisivum to the mouth. 
Several small branches also pass to the nose from the palatine 
and other nerves ; but those already mentioned are the most im- 
portant. 

A question has been proposed, whether the olfactory nerve is 
exclusively concerned in the function of smelling, or whether the 
other nerves above mentioned are also concerned in it. It seems 
probable that this function is exclusively performed by the olfac- 
tory nerve, and that the other nerves are likewise the ophthalmic 
branch of the fifth pair, with respect to the optic nerve. In 
proof of this, it is asserted that the sense of smelling has entirely 
ceased in some cases, where the sensibility to mechanical irrita- 
tion of every kind has remained unchanged. If the olfactory 
nerve alone is concerned in the function of smelling, it follows. 
that this function must be confined to the upper parts of the nasal 
cavities ; but it ought to be remembered, that the structure of 
the Schneiderian membrane, in the lower parts of these cavities, 
appears exactly like that which is above. 

The surface of the nasal cavities and their septum, when co- 



EXTENT OF THE SCHNEIDERIAN MEMBRANE. 425 

vcred with the Schneiderian membrane, correspond with the 
osseous surface formerly described. The membrane covers the 
bones and cartilage of the septum, so as to make one uniform 
regular surface. From the upper part of the septum, it is con- 
tinued to the under side of the cribriform plate of the ethmoid, 
and lines it; the filaments of the olfactory nerve passing through 
the foramina of that bone into the fibrous surface of the mem- 
brane. It is continued from the septum, and from the cribriform 
plate, to the internal surface of the external nose, and lines it. 
It is also continued backwards to the anterior surface of the 
body of the sphenoidal bone; and, passing through the foramina 
or openings of the sphenoidal cells, it lines these cavities com- 
pletely; but in these, as well as the other cavities, its structure 
appears somewhat changed ; it becomes thinner and less vas- 
cular. 

At the above mentioned foramina, in some subjects, it forms a 
plate or fold, which diminishes the aperture considerably. 

From the upper surface of the nasal cavities, the membrane is 
continued downwards over the surface opposite to the septum. 
On the upper flat surfaces of the cellular portions of the ethmoid, 
it forms a smooth uniform surface. After passing over the first 
turbinated bone, or that called after Morgagni, it is reflected into 
the groove, or upper meatus immediately within and under it ; 
the fold formed by the membrane, as it is reflected into the 
meatus, is rather larger than the bone : and the edge of the fold 
therefore extends lower down than the edge of the bone, and 
partly covers the meatus like a flap, consisting only of the double 
membrane. This fold generally continues backwards as far as 
the spheno-maxillary foramen, which it closes; the periosteum, 
exterior to the foramen, passing through it, and blending itself 
with the fibrous surface of the Schneiderian membrane within. 
Here the sphenopalatine nerves and arteries join the membrane. 
Below this meatus, it extends over the middle, (formerly called 
the upper,) turbinated bone, and is reflected or folded inwards on 
the under side of this bone, and continued into the middle meatus 
below it. In the middle meatus, which is partly covered bv the 
last mentioned turbinated bone, there are two foramina;' one 



416 DISTRIBUTION OF SCHNEIDERIAN MEMBRANE. 

communicating with the maxillary sinus, and the other with the 
anterior cells of the ethmoid and the frontal sinuses. The aper- 
ture into the maxillary sinuses is much less in the recent head, 
in which the Schneiderian membrane lines the nose, than it is in 
the bare bones. A portion of the aperture in the bones is closed 
by the Schneiderian membrane, which is extended over it : the 
remainder of the aperture is unclosed; and through this foramen, 
the membrane is reflected so as to line the whole cavity. As a 
portion of the foramen is covered by the membrane, and this 
portion, as well as the other parts of the cavity, is lined by the 
membrane, it is obvious that at the place where the membrane 
is extended over the foramen in the bone, it must be doubled ; or, 
in other words, a part of the aperture of the maxillary sinus is 
closed by a fold of the Schneiderian membrane.* 

This aperture varies in size in different subjects, and is often 
equal in diameter to a common quill. It is situated in the middle 
of the meatus, and is covered by the middle turbinated bone 
immediately above it, is a prominence of the cellular structure 
of the ethmoid bone, which has a curved or semicircular figure. 
Near this prominence, in the same meatus, a groove terminates, 
which leads from the anterior ethmoid cells and the frontal 
sinuses. 

From the middle meatus, the membrane proceeds over the in- 
ferior turbinated bone, and is reflected round and under it into 
the lower meatus. It appears rather larger than the bone which 
it covers ; and therefore the lower edge of the bone does not 
extend so low as the lower edge of the membrane, which of 
course is like a fold or plait. The membrane then continues 
and lines the lower meatus : here it appears less full than it is in 
the turbinated bone. In this meatus, near to its anterior end, is 
the lower orifice of the lachrymal duct ; this is simply lined by 
the Schneiderian membrane, which is continued into it, and 
forms no plaits or folds that affect the orifice. 

* In the mucous membrane lining the cavities of the maxillary, sphenoid and 
ethmoid bones, no one has yet detected any mucous follicles. The pouch formed 
by the reflection of the membrane, seems itself to constitute a large follicle, from 
which mucus is abundantly secreted. — r. 



EUSTACHIAN TUBE. 



417 



Fig. 34. 




Orifice of the Eustachian Tube. 

Immediately behind each of the nasal cavities, on the exter- 
nal side, is the orifice of the Eustachian Tube. It has an oval 

* Fig. 34— is a vertical section, exhibiting a profile view from the inside of the 
cavities of the nostrils, mouth, and pharynx, a, The nose, b, Upper lip, situated 
in front of the palatine arch, which runs horizontally backwards, and divides the 
cavity of the mouth from the nasal fossae, c, The tongue, the base of which is 
attached to the os hyoides d. e, The larynx, suspended from the os hyoides, by 
the thyrco-hoid ligaments which arc seen intervening; it opens backwards towards 
the pharynx. /, Trachea, g, Cuneiform process of the occipital bone, united to 
the body of the sphenoid, and to which is chiefly suspended the pharynx h. i, 
Commencement of the oesophagus, k, Section of the velum pendulum palate, the 
lowei point of which constitutes the uvula; above this is seen the opening of the 
posterior nares, 7, into the top part of the cavity of the pharynx; below this 



418 OBSERVATIONS RESPECTING THE NOSE. 

form, and is large enough to admit a very large quill. Its posi- 
tion is oblique : the upper extremity being anterior to the other 
parts of the aperture, and on a line with the middle meatus, 
while the centre is behind the inferior turbinated bone. The 
lower part of the oval is deficient. This tube is formed poste- 
riorly by a cartilaginous plate. It is lined by the membrane con- 
tinued from the nose. 

The cavities of the nose answer a twofold purpose in the animal economy ; 
they afford a surface for the expansion of the olfactory nerves, and a pas- 
sage for the external air to the windpipe, in respiration. 

The function of smelling appears to be dependent, to a certain degree, upon 
respiration. It has been asserted that unless the air passes in a stream 
through the nose, as in respiration, the perception of odour does not take 
place ; that in persons who breathe through wounds and apertures in the 
windpipe, the function of smelling is not performed. It is rather in con- 
firmation of this proposition, that most persons, when they wish to have 
an accurate perception of any odour, draw in air rapidly through the 
nose. 

Although the ultimate terminations of the olfactory nerves cannot be demon- 
strated like those of the optic and auditory nerves, it is probable, from the 
appearance of the fibres, while they are distinguishable, that they are 
finally arranged with great delicacy. . It is certain that the impressions 
from whence we derive the perceptions of many odours must be very 
slight, as some odorous bodies will impregnate the air of a large cham- 
ber for a great length of time, without losing any sensible weight. 

With respect to delicacy of structure and sensibility, it is probable that the 

are seen the two half arches of the palate, o, Posterior half arch, r, Anterior 
half arch, the space or cavity between these occupied by the tonsil or amygdalae p. 

1, Sublingual gland, placed under the tongue, and communicating with the mouth 
by a small duct, (ductus Bartholinus :) many small ducts from this gland, open 
into the duct of the gland below, in, Sub-maxillary gland, situated below and be- 
hind the preceding gland, n, Thyroid gland, s, Vertical section of the border 
of the cervical vertebra?, to which the pharynx is attached by cellular tissue, t, 
Spinal canal, u, Section of spinous processes and muscles of the neck, v, Left 
nostril, w, Bony palate, x, Trumpet-shaped orifice of the Eustachian tube, y, 
Inferior turbinated bone, covered by the Schneiderian membrane, z, Middle tur- 
binated bone. 1, Superior turbinated bone, both covered with the same membrane. 

2, Superior meatus. 3, Middle meatus. 4, Inferior meatus. 5, Place of open- 
ing of the ductus ad nasum. 6, Frontal sinuses. 9, Sphenoidal cell in the body 
of the sphenoid bone, showing the orifice below, by which it communicates with 
the top of the pharynx ; above is seen the sella turcica of the sphenoid bone. 



USES OP THE SINUSES OP THE NOSE. 4JQ 

nose holds a middle rank between the eye or ear, and the tongue: and on 
this account the mucus is necessary as a covering and defence of its sur- 
face. 

It has been ascertained, by the investigations of chemists, that this mucus 
contains the same ingredients as the tears already described, namely, ani- 
mal mucus and water; and muriate of soda, and soda uncombined; phos- 
phate of lime, and phosphate of soda. 

The animal mucus, which is a most important ingredient in the composi- 
tion, resembles the mucilage formed by some of the vegetable gums in 
several particulars; and differs from them in others. 

The mucus of the nose, if it remain there long after it is secreted, becomes 
much more viscid in consistence, and changes from a whitish colour to 
one which partakes more or less of the yellow. It is probable that an 
incipient putrefaction may occasion these changes in it. 

The use of the frontal, maxillary and other sinuses, communicating with the 
nose, has been the subject of some inquiry. As there can be no stream 
of air through them, and as the membrane lining them is neither so thick, 
villous nor flexible as that lining the nose, it may be concluded, a priori, 
that they are not concerned in the function of smelling. This opinion is 
strengthened by the fact, that very young children, in whom these sinuses 
scarcely exist, enjoy the sense of smelling in perfection. The following 
fact is also in support of it. The celebrated Desault attended a patient, 
in whom one of the frontal sinuses was laid open by the destruction of 
the bone which covered it anteriorly. This patient was able to breathe a 
short time through the sinus when the mouth and nose were closed : at 
the request of Desault he breathed in this manner when a cup of some 
aromatic liquor was held near the opening of the sinus, and had not the 
least perception of odour. This experiment was repeated several times. 

Many physiologists believe that these sinuses have an effect in modulating 
the voice. 



420 0F THE MOUTH. 



CHAPTER XIII. 

OF THE MOUTH. 

The general cavity of the mouth is formed anteriorly and 
laterally by the connexion of the lips and cheeks to the upper 
and lower jaws; so that the teeth and the alveoli of both jaws 
may be considered as within the cavity. Above, it is bounded 
principally by the palatine processes of the upper maxillary and 
palate bones, and the soft palate, which continues backward from 
them in the same direction. 

Below, the cavity is completed by several muscles, which pro- 
ceed from almost the whole internal circumference of the lower 
jaw, and, by their connexions with each other, with the tongue 
and the os hyoides, form a floor or bottom to it. The tongue is 
particularly connected to this surface, and may be considered as 
resting upon and supported by it. 

To acquire an idea of the parietes of this cavity, after study- 
ing the upper and lower maxillary bones, the orbicularis oris 
and the muscles connected with it, especially the buccinator, 
ought to be examined ; and also the diagastricus, the mylo-hyoi- 
deus, genio-hyoideus, and genio-hyoglossus. By this it will ap- 
pear that the lips and cheeks, and the basis or floor of the mouth, 
are formed in a great measure by muscles. Upon the internal 
surface of these muscles, a portion of cellular and adipose sub- 
stance is arranged, as well as glandular bodies of different sizes; 
and to these is attached the membrane which lines the inside of 
the mouth. 

This membrane passes from the skin of the face to the lips, 
and the inside of the mouth ; and, although it is really a continu- 
ation of the skin, there is so great a change of structure that it 
ought to be considered as a different membrane. At the orifice 



INTERNAL SURFACE OF THE MOUTH.-GUMS. 49 J 

of the lips it is extremely thin, and so vascular, that it produces 
the fine florid colour which appears there in health. It is co- 
vered by a cuticle, called by some anatomists, Epithelium, which 
has a proportionate degree of delicacy, and can be separated 
like the cuticle in other parts. When this cuticle is separated, 
the lips and the membrane of the mouth appear to be covered 
with very fine villi, which are particularly apparent in some pre- 
parations of the lips after injection and maceration.* 

Under this membrane are many small glandular bodies of a 
roundish form, called glandulse labiales, whose excretory ducts 
pass through it to the inner surface of the mouth, for the pur- 
pose of lubrifying it with their secretion, which is mingled with 
the saliva. 

The membrane which lines the inside of the lips and cheeks, 
is somewhat different from that which forms the surface of the 
orifice of the mouth : it is not so florid ; the blood-vessels in its 
texture are larger, and not so numerous. This change, how- 
ever, takes place very gradually, in the progress of the mem- 
brane, from the orifice of the lips to the back part of the cheeks. 
Glandular bodies, like those of the lips, are situated immediately 
exterior to this membrane of the cheeks, between it and the mus- 
cles : their ducts open on its surface. These glands are called 
Bucca/es. 

This lining membrane is continued from the internal surface 
of the lips and cheeks to the alveolar portions of the upper and 
lower jaws, which are in the cavity of the mouth, and covers 
them, adhering firmly to the periosteum. 

The teeth appear to have passed through apertures in this 
membrane, and are surrounded by it closely at their respective 
necks. 

The portion of membrane, which thus invests the jaws, con- 
stitutes therms; which have now acquired a texture very dif- 
ferent from that of the membrane from which they were con- 

* Ruysch had a fine preparation of this structure. See Thesaurus VII. Tab. 
III. Fig. 5. 

vol. i. 36 



422 MEMBRANE LINING THE HARD OR BONY PALATE. 

tinued. They are extremely firm and dense, and very vascular 
It is probable that their ultimate structure is not perfectly under- 
stood. 

In the disease called scurvy, they tumefy and lose the firmness 
of their texture : they acquire a livid colour, and are much dis- 
posed to hemorrhage. 

From the alveoli of the upper jaw, the lining membrane is 
continued upon the palatine processes of the upper maxillary 
and palate bones, or the roof of the mouth. 

The membrane of the palate is not quite so firm as that of the 
gums, and is also less florid : it adheres firmly to the periosteum, 
and thus is closely fixed to the bones. There is generally a ridge 
on its surface, immediately under the suture between the two up- 
per maxillary bones ; and some transverse ridges are also to be 
seen upon it. On the internal surface of this membrane are small 
glandular bodies, whose ducts open on the surface of the palate. 

It is asserted, that this membrane has a limited degree of that 
sensibility which is essential to the functions of tasting ; and that 
if certain sapid substances are carefully applied to it, their re- 
spective tastes will be perceived, although they have not been in 
contact with the tongue. 

The membrane is continued from the bones above mentioned 
to the soft palate, or velum pendulum palati, which is situated 
immediately behind them. This soft palate may be considered 
as a continuation of the partition between the nose and mouth ; 
it is attached to the posterior edge of the palatine processes of 
the ossa palati, and to the pterygoid process of the sphenoidal 
bone. Its interior structure is muscular. The upper surface is 
covered by the membrane of the nose, the lower surface by the 
membrane which lines the mouth. 

The muscles, which contribute to the composition of this 
structure, are the circumflexi and the levatores palatine above, 
and the constrictors isthmi faucium and palato-pharyngei below. 
(See pages 290 — 291.) Thus composed, the soft palate consti- 
tutes the back part of the partition between the nose and 
mouth. When viewed from before, with the mouth open, it pre- 



SOFT PALATE—UVULA. 42 3 

sents towards the tongue an arched surface, which continues 
downwards on each side, until it comes nearly in contact with 
the edges of that organ. On each of the lateral parts of this 
arch, are two pillars, or rather prominent ridges, which project 
into the mouth. These ridges are at some distance from each 
other below, and approach much nearer above, so that they in- 
clude a triangular space. They are called the lateral half arches 
of the palate, (see Fig. 34, p. 417.) Each of them is formed by 
a plate or fold of the lining membrane of the mouth, and con- 
tains one of the two last mentioned muscles : the anterior, the 
constrictor isthmi faucium; the posterior, the palato-pha'ryn- 
geus. These muscles, of course, draw the palate down toward 
the tongue when they contract. 

From the centre of the arch, near its posterior edge, is sus- 
pended the uvula, a conical body, which varies in length from 
less than half an inch, to rather more than one inch. It is con- 
nected by its basis to the palate ; but its apex is loose and pendu- 
lous. This body is covered by the lining membrane of the 
mouth. It contains many small glands, and a muscle also, the 
azygos uvula?, which arises from the posterior edge of the ossa 
palati, at the suture which connects them to each other, and, pass- 
ing posteriorly upon the soft palate, extends from the basis to the 
apex of the uvula, into which it is inserted. By the action of this 
muscle, the length of the uvula can be very much diminished: 
and when its contraction ceases, that body is elongated. 

The pendulous part of the uvula can also be moved, in certain 
cases, to either side. 

It is commonly supposed, that the principal use of this little or- 
gan is to modulate the voice; but there are good reasons for be- 
lieving, that it has another object. It was remarked by Fallo- 
pius, (and the observation has been confirmed by many surgeons 
since his time,) that the uvula may be removed completely with 
out occasioning any alteration of the voice, or anv difficulty of 
deglutition, if the soft palate be left entire. 

The soft palate is so flexible, that it yields to the actions of 
the levatores palati, which draw it up so as to close the posterior 
nares completely. 



424 THE TONGUE. 

It also yields to the circumflexi or tensores, which stretch it 
so as to do away its arched appearance. 

It is therefore very properly called the Palatum Molle, or soft 
palate. It is also frequently called the Velum Pendulum Palati, 
from the position which it assumes. 

The Tongue, 

Which is a very important part of this structure, is retained 
in its position and connected with the parts adjoining it, by the 
following arrangements. 

The os hyoides, which, as its name imports, resembles the 
Greek letter u, or half an oval, is situated rather below the 
angles of the lower jaw, in the middle of the upper part of the 
neck. It is retained in its position by the sterno-hyoidei muscles, 
which connect it to the upper part of the sternum, by the coraco, 
or omo-hyoidei, which pass to it obliquely from the scapula ; by 
the thyro-hyoidei, which pass to it directly upward from the thy- 
roid cartilage, all of which connect it to parts below. To these 
should be added the stylo-hyoidei, which pass to it obliquely 
from behind and rather from above : the mylo-hyoidei, which 
come rather anteriorly from the lateral parts of the lower jaw ; 
and the genio-hyoidei, which arises from a situation directly an- 
terior and superior to the chin. When these muscles are at rest, 
the situation of the os hyoides is, as above described, below the 
angles of the lower jaw : when those, in one particular direc- 
tion act, while the others are passive, the bone may be moved 
upwards or downwards, backwards or forwards, or to either 
side. This bone may be considered as the basis of the tongue ; 
for the posterior extremity of that organ is attached to it, and of 
course the movements of the bone must have an immediate ef- 
fect upon those of the tongue. 

The tongue is a flat body of an oval figure, but subject to con- 
siderable changes of form. 

The posterior extremity, connected to the os hyoides, is com- 
monly called its basis ; the anterior extremity, which, when the 
tongue is quiescent, is rather more acute, is called its apex. 

The lower surface of the tongue is connected with a numbei 



STRUCTURE OF THE TONGUE 425 

of muscles, which are continued into its substance. This con- 
nexion is such, that the edges of the tongue are perfectly free 
and unconnected ; and so is the anterior extremity for a consi- 
derable distance from the apex towards the base. 

The substance of the tongue consists principally of muscular 
fibres intermixed with a delicate adipose substance. It is con- 
nected to the os hyoides by the hyo-glossus muscle, and also by 
some other muscular fibres, as well as by a dense membranous 
substance, which appears to perform the part of a ligament. 
This connexion is also strengthened by the continuance of the 
integuments from the tongue to the epiglottis cartilage, to be 
hereafter described ; for that cartilage is attached by ligaments 
to the os hyoides. 

The tongue is thin at its commencement at the os hyoides ; 
but it soon increases in thickness. The muscular fibres in its 
composition have been considered as intrinsic, or belonging 
wholly to its internal structure ; and extrinsic, or existing in part 
outside of this structure. The lingualis muscles are intrinsic 
(see page 288) : they are situated near the under surface of 
the tongue, one on each side, separated from each other by the 
genio-hyo-glossi muscles, and extending from the basis of the 
tongue to its apex. These muscles can be easily traced as above 
described : but there are also many fibres in the structure of the 
tongue, which seem to pass in every direction, and of course are 
different from those of the lingualis muscles. To these two sets 
of fibres are owing many of the immensely varied motions of 
the different parts of the tongue. 

— According to Gerdy, (whose researches on this subject have 
been approved by Ribes and Breschet,) the structure of the 
tongue consists of the mucous membrane forming its outer coat, 
of a peculiar yellow lingual tissue, which forms the ligament 
by which it is attached to the os hyoides, and is extended along 
the middle line of the tongue to form a sort of raphe for the 
attachment of the transverse muscular fibres, and of the in- 
trinsic and extrinsic muscles, mixed up with some delicate cel- 
lular and adipose tissue. The intrinsic muscles consist, 1st, of a 
superficial lingual muscle ; 2d, of two deep-seated, all of which 

36* 



426 STRUCTURE OF THE TOXGUE. 

are longitudinal; 3d, of transverse muscular fibres, reunited at 
the raphe, in the middle line of the tongue ; 4th, of some vertical 
fibres which are inserted on the lower surface of the mucous 
membrane. The ligament from the os hyoides extended along 
the middle line of the tongue, Blandin calls the lingual carti- 
lage. The evidence in favour of its cartilaginous nature, is not 
very satisfactory in man. The epidermis of the tongue, which is 
much thicker than that of other portions of the mouth, forms, 
according to Blandin, a sheath round the sensitive papillae, open 
at top, which protects them, when the tongue acts, as an instru- 
ment of mastication, and through which the papilla? protrude, 
to come fully in contact with the sapid substance when tumefied 
or erected by the gustatory excitement. — 

In addition to these, are the extrinsic muscles, which originate 
from the neighbouring parts, and are inserted and continued into 
the substance of the tongue. 

Among the most important of the muscles, are those which 
proceed from the chin, or the genio-hyo-glossi. They are in 
contact with each other; their fibres radiate from a central point 
on the inside of the chin, and are inserted into the middle of the 
lower surface of the tongue : the insertion commencing at a short 
distance from its apex, and continuing to its base. 

As the genio-hyo-glossi muscles have a considerable degree 
of thickness, they add much to the bulk of the tongue in the 
middle of the posterior parts of it. 

The hyo-glossi and the stylo-glossi, being continued into the 
posterior and lateral parts, contribute also to the bulk of these 
parts. 

The tongue, thus composed and connected, lies, when at rest, 
on the mylo-hyoidei muscles ; and the space between it and these 
muscles is divided into two lateral parts by the above described 
genio-hyo-glossi. In the space above mentioned, is a small sali- 
vary gland, of an irregular oval form ; the greatest diameter of 
which extends from before backwards, and its edges present out- 
wards and inwards. It has several excretory ducts, the orifices 
of which form a line on each side of the tongue. This gland is 



PAPILLA OF THE TONGUE. 427 

very prominent under the tongue ; and when the tongue is raised 
it is particularly conspicuous : it is called the Sublingual. 

The lining membrane of the mouth continues from the inside 
of the alveoli of the lower jaw, which it covers, over the sublin- 
gual glands to the lower surface of the tongue. In this situation 
it is remarkably thin; but, as it proceeds to the upper surface of 
the tongue, its texture changes considerably, and on this surface 
it constitutes the organ of taste. 

The upper surface of the tongue, although it is continued from 
the thin membrane above described, is formed by a rough inte- 
gument which consists, like the skin, of three lamina. The cu- 
ticle is very thin ; and under it, the rete mucosum* is thicker 
and softer than in other places. 

The true skin here abounds with eminences of various sizes 
and forms, all of which are denominated Papilla. The largest 
of these are situated on the posterior part of the tongue, and are 
so arranged that they form an angle rather acute, with its point 
backwards. They are commonly nine in number : they resemble 
an inverted cone, or are larger at their head than their basis. 
They are situated in pits or depressions, to the bottoms of which 
they are connected. In many of them there are follicles, or 
perforations, which have occasioned them to be regarded as 
glands. They are called Papillce Mazimce, or Capitatce. 

The papillae, next in size, are denominated fungiform by some 
anatomists, and Mediae, or Semilenticulares by others. They 
are nearly cylindrical in form, with their upper extremities regu- 
larly rounded. They are scattered over the upper surface of the 
tongue, in almost every part of it, at irregular distances from 
each other. 

The third class are called conoidal or villous. They are very 
numerous, and occupy the greatest part of the surface of the 
tongue. Although they are called conoidal, there is a great dif- 
ference in their form ; many of them being irregularly angular 
and serrated as well as conical. 

* M. Bichat appears to have had doubts whether the real rete mucosum existed 
here. He says that he could only perceive a decussation of vessels in the inter- 
vals of the papilloe, which, as he supposes, occasioned the florid colour of the 
tongue. 



428 PAPILLAE "OF THE TONGUE. 

Soemmering and other German anatomists consider the 
smallest papillae as a fourth class, which they call the filiform : 
these lie between the others. 

It is probable that these papillae are essential parts of the or- 
gan of taste ; and their structure is of course an interesting ob- 
ject of inquiry. 

The nerves of the tongue have been traced to the papillae, and 
have been compared by some anatomists to the stalk of the ap- 
ple, while the papillae resembled the fruit ; but their ultimate ter- 
mination does not appear to have been ascertained.* 

— The papillae maximae or capitatae, are supplied, according 
to Cloquet, by filaments from the glosso-pharyngeal nerve, the 
fungiformes by filaments from the fifth. The papillae maximae 
appear to consist only of a collection of mucous follicles, which 
differ only from those of the soft palate and lips, by standing 
out more in relief. 

— The follicles of each papilla open occasionally upon the side ; 
several open by a common orifice at the top of the papilla, which 
is often very visible to the naked eye, as a little reddish point. 
Weber succeeded in injecting this orifice with mercury, and 
found it led to a central cavity irregularly divided by septae into 
cells, visible to the naked eye, having some resemblance to, but 
much larger than those of the parotid. Other mucous follicles 
of a simpler kind are spread over the whole surface of the 
tongue between the smaller papillae. Some are mere small 
pouches, opening by simple orifices, without canals. Others 
are more complicated, and according to Weber, who filled them 
with mercury, have ducts three or four lines in length, which 
run down between the muscular fibres of the tongue, to termi- 
nate in little flattened sacs divided into several cells, and having 
sometimes, a diameter of three lines. 

— From all these follicles, comes that profusion of mucous secre- 
tion, which we see covering the tongue in diseases. 

* In the explanation of the plates, referred to in the following sentence, Soem- 
mering observes, that when the fibrillar of the lingual nerve of the fifth pair are 
traced to the papillae of the second class, they swell out into a conical form ; and 
these nervous cones are in such close contact with each other, that the point of the 
finest needle could not be insinuated into the papilla? without touching a nerve. 



BLOOD-VESSELS OF THE TONGUE. 429 

— He describes the sebaceous glands of the skin as being ana- 
logous in structure to these follicles, as well as those of the tra- 
chea, and of the inside of the lips and cheeks. — 

Soemmering has lately published some elegant engraved co- 
pies of drawings of these papillae, when they were magnified 
twenty-five times; from which it appears that a very large 
number of vessels, particularly of arteries, exist in them. These 
vessels are arranged in a serpentine direction, and are prominent 
on the surface ; but they appear doubled, and the most prominent 
part is the doubled end. — This arrangement of vessels is per- 
ceptible on the sides of the tongue, as well as on the papilla?. 

Behind the large papillae is a foramen, first described by Mor- 
gagni, and called by him Foramen Caecum. It is the orifice of 
the cavity which is not deep; the excretory ducts of several 
mucous glands open into it. 

On the upper surface of the tongue, a groove is often to be 
seen, which is called the tinea mediana, and divides it into two 
equal lateral parts.* Below, the lining membrane of the mouth, 
as it is continued from the lower jaw to the tongue, forms a plait, 
which acts as a ligament, and is called the frcenum linguce. It 
is attached to the middle of the tongue, at some distance behind 
the apex. 

The tongue is well supplied with blood-vessels, which are de- 
rived from the lingual branch of the external carotid on each 
side. This artery passes from the external carotid, upwards, 
inwards, and forwards, to the body of the tongue. In this course 
it sends off several small arteries to the contiguous parts, and 
one which is spent about the epiglottis and the adjoining parts, 
called the Dorsalis Linguce. About the anterior edge of the 
hyo-glossus muscle, it divides into two large branches : one of 
which, called the Sublingual, passes under the tongue between 
the genio-hyo-glossus and the sublingual gland, and extends near 
to the symphysis of the upper jaw; sending branches to the sub- 
lingual gland, to the muscles under the tongue, to the skin, and 
the lower lip. The other is in the substance of the tongue, on 
the under side near the surface, and extends to the apex. 

* Tliis groove indicates tlie position of the middle raphe of Gerdy. — p. 



430 THE SALIVARY GLANDS. 

The veins of this organ are not so regular as the arteries: 
they communicate with the external jugular, and some of them 
are always very conspicuous under the tongue : these are called 
ranular. 

It is to be observed, that the vessels on each side have but 
little connexion with each other; for those of one side may be 
injected while the others continue empty. 

The tongue is also well supplied with nerves, and derives them 
from three different sources on each side, namely, from the fifth, 
the eighth, and ninth pairs of the head. 

The lingual portion of the third branch of the fifth pair passing 
under the tongue, enters its substance about the middle, and 
forms many minute branches, which pass to the papillae of the 
forepart of the tongue. 

The glossopharyngeal portion of the eighth pair, sending off 
several branches in its course, passes to the tongue near its basis, 
and divides into many small branches, which are spent upon the 
sides and middle of the root of the tongue, and also upon the 
large papillae. 

The ninth pair of nerves are principally appropriated to the 
tongue. They pass on each side to the most fleshy part of it, 
and after sending one branch to the mylo-hyoideus, and another 
to communicate with the lingual branch of the fifth pair, they are 
spent principally upon the genio-glossi, and linguales muscles. 

The tongue answers a threefold purpose. It is the principal 
organ of taste. It is a very important agent in the articulation 
of words, and it assists in those operations upon our food, which 
are performed in the mouth. 

The Salivary Glands. 

The salivary glands have such an intimate connection with 
the mouth that they may be described with it.* 

There are three principal glands on each side : the Parotid, 
Submaxillary, and the Sublingual They are of a whitish or 
pale flesh colour, and are composed of many small united masses 

* For a further account of glands, see General Anatomy of Glandular System. 



PAROTID GLAND. 431 

or lobuli, each of which sends a small excretory duct to join 
similar ducts from the other lobuli, and thereby form the great 
duct of the gland. 

The Parotid is much larger than the other glands. It occupies 
a large portion of the vacuity between the mastoid process and 
the posterior parts of the lower jaw. It extends from the ear 
and the mastoid process over a portion of the masseter muscle, 
and from the zygoma to the basis of the lower jaw, (see Fig. 7, 
plate xiii.) Its name is supposed to be derived from two Greek 
words which signify contiguity to the ear. It is of a firm con- 
sistence. It receives branches from the external carotid artery 
and from its facial branch. 

From the anterior edge of this gland, rather above the middle, 
the great duct proceeds anteriorly across the masseter muscle; 
and, after it has passed over, it bends inward through the adipose 
matter of the cheek to the buccinator muscle, which it perforates 
obliquely, and opens on the inside of the cheek opposite to the 
interval between the second and third molar teeth of the upper 
jaw. The aperture of the duct is rather less than the general 
diameter of it, and this circumstance has the effect of a valve. 
When the duct leaves the parotid, several small glandular bodies 
called socia? parotidis, are often attached to it, and their ducts 
communicate with it. The main duct is sometimes called ductus 
stenonianus, after Steno, who first described it. 

When the mouth is opened wide, as in gaping, there is often 
a jet of saliva from it into the mouth. 

The parotid gland furnishes the largest proportion of saliva. 

It covers the nerve called Portio Dura, after it has emerged 
from the foramen stylo-mastoideum. 

— This nerve after being covered a short distance by the gland, 
enters its substance, so as to form there the plexus called pes 
anserinus, so as to leave a portion of the gland on the inner face 
of the nerve. The external carotid artery likewise traverses the 
gland situated rather more exterior than the nerve, so as to leave 
about one-third of the gland on its inner face. Branches from 
the artery are sent off in various directions as it traverses the 
gland, to the face, and to the structure of the gland itself. 



432 ULTIMATE STRUCTURE OF THE SALIVARY GLANDS. 

— The duct of Steno, is very feebly attached to the surround- 
ing parts, and is accompanied by many branches of the middle 
division of the facial nerves, and some small arteries which supply 
its walls; it is covered only by the skin, some adipose tissue, by 
some fibres of the platysma myoides, and the zygomaticus major, 
which crosses it obliquely. Its general diameter is about a line ; 
and it is very distensible. It will be found, according to the rule 
laid down by Dr. Physick, under a line drawn from the lobe of 
the ear, to the tip of the nose. 

— The duct is composed of two coats, one, external, white, fibrous, 
and resisting ; the other, internal, is a mucous membrane, con- 
tinuous with the lining membrane of the mouth, and appears to 
differ from it only in being paler. 

— Fig. 35, is a microscopical representation 
Fig. 35. of the structure of a portion of the parotid 
gland of a young infant, after it had been 
minutely injected with mercury from the 
duct of Steno, by E. H. Weber, of Leipzic. 
The small figure, to the right, is the natural 
size of the piece magnified, in which the sali- 
vary ducts were filled with the fluid to their 
very terminations. In the larger figure it is 
magnified fifty diameters. A branch of the 
salivary duct, is seen on the right margin of 
this figure, ramifying like the branch of a tree. These ramifica- 
tions never anastomose together, and are of much larger size 
than the capillary blood-vessels. Each ramification, at its ter- 
mination, resolves itself into cells, densely compacted together, 
like a bunch of grapes upon its stem a, a, a. Some of the cells 
open by a minute excretory tube directly into the salivary duct. 
In other instances some of the ducts of the cells unite into a 
common tube, before entering the salivary duct. The cells are 
not round, and vary among themselves in regard to size. 
The average diameter of these cells, measured by a micro- 
meter, were found by Weber, to be the T - 2 Wh part of an inch, 
which he finds to be three times greater than that of the most 
delicate sanguineous vessels. The cellular structure of the pa- 




THE SUBMAXILLARY GLAND. 



433 



rotid, seems therefore to be very analogous to the cellular struc- 
ture of the lungs discovered by Soemmering and Reisseissen. 
The cells of the lungs, however, being five or six times larger 
than those of the parotid. The elaborate researches of Weber 
and Muller, have shown also that this is the common mode of 
termination of the excretory ducts in the different glands of the 
body; viz. that they terminate in closed cells, upon which ramify 
the delicate secretory capillary vessels. — 

The second gland is called the Submaxillary. It is much 
smaller than the parotid, and rather round in form. It is situated 
immediately within the angle of the lower jaw, between it on the 
outside, and the tendon of the digastric muscle and the ninth 
pair of nerves internally. Its posterior extremity is connected 
by cellular membrane to the parotid gland ; its anterior portion 
lies over a part of the mylo-hyoideus muscles ; and from it pro- 
ceeds the excretory duct, which is of considerable length, and 
passes between the mylo-hyoideus and genio-glossus muscles 
along the under and inner edge of the sublingual gland. In this 
course the duct is sometimes surrounded with small glandular 
bodies, which seem to be appendices to the sublingual gland. It 
terminates under the tongue, on the side of the fraenum linguae, 
by a small orifice which sometimes forms a papilla.* (See Fig. 34, 
p. 417.) 

The orifice is often smaller than the duct ; in consequence of 
which, obstruction frequently occurs here, and produces the 
disease called ranula. 

The sublingual gland, which has already been mentioned, lies 
so that, when the tongue is turned up, it can be seen protruding 
into the cavity of the mouth, and covered by the lining membrane, 
which seems to keep it fixed in its place. It lies upon the mylo- 
hyoideus, by the side of the genio-hyoideus; and is rather oval 
in form, and flat. Its greatest length is from before backwards ; 

* Lassus informs us that Oribases, afterwards all the Arabians, and subsequently 
Guy De Chauliac, Lanfranc, Achillini, Berenger De Carpi, Charles Etienne, Cas- 
serius and several others have given the description of these salivary ducts ; not- 
withstanding which, Wharton, a physician of London, attributed to himself the 
discovery of them on the bullock, in 1656. — h. 
vol. i. 37 



434 SUBLINGUAL GLAND. 

its position is rather oblique, one edge being placed obliquely in- 
wards and upwards, and the other outwards and downwards. 
It has many short excretory ducts, which open by orifices ar- 
ranged in a line on each side: they are discovered with difficulty 
on account of their small size, and sometimes amount to eighteen 
or twenty in number. In some few instances, this gland sends 
off a single duct, which communicates with the duct of the sub- 
maxillary gland. 

— The duct of the Submaxillary gland is called the duct of 
Wharton, {ductus Whartonionus) from an English anatomist who 
first described it. It is accompanied in nearly the whole of its 
course by the lingual branch of the fifth pair of nerves. 
— The usual arrangement of the ducts of the sublingual gland 
is as follows : six or eight run from the upper part of the gland, 
to open by the side of the frsenum linguae. Five or six others 
proceed from its sides to open separately in the mucous mem- 
brane above the gland. Several open into the duct of Wharton 
which runs by the side of the gland ; these most frequently unite 
to form a single duct, called the duct of Bartholinus, or duct of 
Rivinus. This I have frequently succeeded in distending with 
mercury from the duct of Wharton. 

— The structure and office of these salivary glands appear the 
same, and not unfrequently a slight continuation of structure is 
observed at the two extremities of the submaxillary gland. — 

The salivary fluid secreted by these glands is inodorous, in- 
sipid, and limpid, like water; but much more viscid, and of 
greater specific gravity. Water constitutes at least four-fifths of 
its bulk ; and animal mucus one half of its solid contents. It also 
contains some albumen, and several saline substances; as the 
muriate of soda, and the phosphates of lime, of soda, and of am- 
monia. 

It is probable that this fluid possesses a solvent power with 
respect to the articles of food. 

There are small glandular bodies, situated between the masse- 
ter and buccinator muscles, opposite to the last molar tooth of 
the upper jaw, whose nature is not well understood : they are 
called Glandulce Molares. 



OBSERVATIONS ON THE TONGUE. 405 

The motions of the tongue are very intelligible to a person who has a prepa- 
ration of the lower jaw before him, with the tongue in its natural situation, 
and the muscles which influence it, properly dissected. Its complicated 
movements will appear the necessary result of the action of those muscles 
upon it, and the os hyoides; and also upon the larynx, with which the os 
hyoides is connected. The muscular fibres of the tongue itself are also 
to be taken into this view, as they act a very important part. 

Although the tongue appears very necessary, in a mechanical point of view, 
to the articulation of many words, yet there are cases where it has been 
entirely deficient, in which the parties thus affected, have been able to 
^ speak very well in general, as well as to distinguish different tastes.* 

The tongue is also a very delicate organ of touch.— We can perceive the 
form of the teeth, and the state of the surface of the mouth, more accu- 
rately by the application of the tongue than of the fingers. 

On the three nerves which go to the tongue, it is generally supposed that 
the lingual portion of the third branch of the fifth pair is most immediately 
concerned in the function of tasting, as it passes to the front part of the 
surface of the tongue. The glosso- pharyngeal are probably concerned in 
the same function on the posterior part, while the ninth pair of nerves 
seems principally spent upon the muscular parts of the organ. 

It is obvious that the tongue is most copiously supplied with nerves. This 
probably accounts for the great facility of its motions, and the power of 
continuing them. 

* There is a very interesting paper on this subject, in the Memoirs of the Aca 
demy of Sconces for the year 1718, by Jussieu; in which he describes the case 
of a female, fifteen years old, examined by himself, who was born without a tongue 
In thu paper he refers to another case, described by Holland, a surgeon of Saumur 
of a boy nine years old, whose tongue was destroyed by gangrene. In each of 
these cases the subject was able to articulate very well, with the exception of a few 
letters ; and also enjoyed the sense of taste. 



436 0F THE THROAT. 



CHAPTER XIV. 



OF THE THROAT. 



To avoid circumlocution, the word throat is used as a general 
term to comprehend the structure which occurs behind the nose 
and mouth, and above the oesophagus and trachea. This struc- 
ture consists, 

1st. Of the parts immediately behind the mouth, which con- 
stitutes the Isthmus of the Fauces : 

2d. Of the parts which form the orifice of the windpipe, or 
the Larynx ; — and 

3d. Of the muscular bag, which forms the cavity behind the 
nose and mouth, that terminates in the oesophagus or the 
Pharynx. 

Of the Isthmus of the Fauces. 

In the back part of the mouth, on each side, are to be seen the 
two ridges or half arches, passing from the soft palate to the root 
of the tongue, (see Fig. 34, p. 417,) formed by plaits of the mu- 
cous membrane, containing muscular fibres. The anterior plait, 
which contains the muscle called Constrictor Isthmi Faucium, 
passes directly from the side of the root of the tongue to the 
palate, and terminates near the commencement of the uvula. 
The posterior plait runs from the palate obliquely downwards 
and backwards, as it contains the palato-pharyngeus muscle, 
which passes from the palate to the upper and posterior part of 
the thyroid cartilage. 

In the triangular space between these ridges is situated a 
glandular body, called the Tonsil or Amygdala.* This gland 

* It is named amygdala, from its resemblance in form and appearance to an 
almond covered by its shell. The exterior or adhering surface of the tonsil gland 



TONSILS.— EPIGLOTTIS. 437 

has an oval form, its longest diameter extending from above 
downwards. Its surface is rather convex, its natural colour is 
a pale red. On its surface are the large orifices of many cells 
of considerable size, which exist throughout the gland. These 
cells often communicate with each other, so that a probe can be 
passed in at one orifice and out at the other. 

Into these cells open many mucous ducts, which discharge in 
part the mucus of the throat, for the purpose of lubricating the 
surface, and facilitating the transmission of food. 

— In its healthy state, the free surface of the tonsil glands, are 
a little below the level of the two half arches of each side. 
— But when its cells are distended by inflammation, or effaced 
by granulations, as in tonsillitis, they sometimes project beyond 
the half arches so as nearly or quite to meet in the middle line. — 

The epiglottis, or fifth cartilage of the larynx, is situated at 
the root of the tongue, in the middle, between the tonsils. The 
part which is in sight is partly oval in form, and of a whitish 
colour. Its position, as respects the tongue, is nearly perpendi- 
cular, and its anterior surface rather convex. 

The mucous membrane continued from the tongue over the 
epiglottis is so arranged that it formes a plait, which extends 
from the middle of the root of the tongue along the middle of the 
anterior surface of the epiglottis, from its base upwards. 

On each side of this plait or frsenum, at the junction of the 
surfaces of the tongue and of the epiglottis there is often a de- 
pression, in which small portions of food sometimes remain ; and 
a small fracnum, similar to that above described, is sometimes 
seen on the outside of each of these cavities. 

The epiglottis is situated immediately before the opening into 
the larynx. 

The above described parts can be well ascertained in the 

is connected by the means of cellular tissue to the superior constrictor muscle of 
the pharynx. 

The internal carotid artery is situated behind and to the outer side of the tonsil, 
and separated from it only by the constrictor muscle, and cellular tissue. 

It has been wounded in opening abscesses of the tonsils, when the cutting in- 
strument has been inclined too much outwards and backwards.— p. 

37* 



438 0F THE LARYNX. 

living subject, by a person who has a general knowledge of the 
structure. Thus, looking into the mouth, with the tongue de- 
pressed, the uvula and soft palate are in full view above, and the 
epiglottis is very perceptible below ; while the two ridges or 
lateral half arches can be seen on each side, with the tonsil be- 
tween them. 

Of the Larynx. (See Plate V. Fig. 14.) 

— The larynx is situated immediately below the os hyoides, and 
is continuous at its inferior part with the trachea, to which it is 
attached, like a capital upon a column. It serves a double pur- 
pose ; that of a tube for the introduction of air into the lungs: 
and that of a very complicated apparatus for the production of 
the voice. 

— It is composed of cartilages which form its frame-work, liga- 
ments and synovial capsules which unite the cartilages together, 
muscles to put them into motion, and an exquisitely sensitive 
mucous membrane, that lines the whole of its interior. It is 
larger and much more prominent in males than females, and un- 
dergoes a rapid and remarkable degree of developement, both 
in regard to size and energy of function at the period of pu- 
berty. — 

In this structure are five cartilages, upon which its form and 
strength depends, namely, the Cricoid, the Thyroid, the two Ary- 
tenoid, and the Epiglottis. These cartilages are articulated to 
each other, and are supplied with muscles by which certain 
limited motions are effected. 

The basis of the structure is a cartilaginous ring, called the 
cricoid cartilage, and which may be considered as the com- 
mencement of the windpipe. 

It may be described as an irregular section of a tube : its 
lower edge connected with the windpipe, being nearly horizontal 
when the body is erect ; and the upper edge very oblique, slop- 
ing from before, backwards and upwards; in consequence of 
this, it has but little depth, before, but is eight or nine lines deep 
behind. 

— In front, and upon each side of the middle line there is a 






CRICOID CARTXLAGE.-THYROID CARTILAGE. 439 

depression, in which arises the two crico-thyroid muscles. Upon 
each side, and near its upper and outer surface, there is a smooth 
convex facette, upon which is articulated, the corresponding facet 
of the inferior cornua of the thyroid cartilage. Posteriorly are 
two slight vertical depressions, to which are attached the crico- 
arytenoidei postici muscles. Its internal face is covered by 
mucous membrane. Its superior border gives attachment in 
front to the crico-thyroid membrane, on the sides to the lateral 
crico-arytenoid muscles, and posteriorly presents a little notch, 
limited by two convex facets upon which are articulated the 
arytenoid cartilages. — 

The Thyroid cartilage is a single plate, bent in such manner 
that it forms an acute angle with two similar broad surfaces on 
each side of it. It is so applied to the cricoid cartilage, that the 
lower edge of the angular part is at a small distance above the 
front part of that cartilage, and connected to it by ligamentous 
membrane; while its broad sides are applied to it laterally, and 
thus partially enclose it. 

The upper edge of the angular part of the thyroid cartilage 
forms a notch ; and the natural position of the cartilage is such, 
that this part is very prominent in the neck ; it is called the Po- 
mum Adami. 

Both the upper and lower edges of the thyroid cartilage ter- 
minate posteriorly in processes, which are called Cornua. The 
two uppermost are longest : they are joined by ligaments to the 
extremities of the os hyoides. The lower and shorter processes 
are fixed to the cricoid cartilage. The thyroid cartilage, there- 
fore partly rests upon the cricoid cartilage below, and is attached 
to the os hyoides above. It is influenced by the muscles which 
act upon the os hyoides, and also by some muscles which are 
inserted into itself. It is moved obliquely downwards and for- 
wards in a slight degree upon the cricoid cartilage, by a small 
muscle, the crico-thyroideus, which arises from that cartilage and 
is inserted into it. 

— The external lateral surface of the thyroid cartilage is 
slightly concave, and across it, passes a small ridge obliquely 
from above downwards, and from behind forwards, which gives 
attachment above to the thvro-hvoid and below to the sterno- 




440 ARYTENOID CARTILAGES. 

hyoid muscles. The posterior or inside face of the Pomum 
Adami presents an entering angle, where the two symmetrical 
sides of the cartilage meet, and in which is attached the thyro- 
arytenoid muscles, the pedicle of the epiglottis and one end of 
the vocal ligaments. The upper margin of the cartilage pre- 
sents a curved appearance like that of the italic long f\ a simi- 
lar curvature is also observable on its posterior margin. — 

The Arytenoid cartilages are two small bo- 
dies of a triangular or pyramidal form and 
slightly curved backward. They are placed c 
upon the upper and posterior edge of the cri- 
coid cartilage, near to each other; and their 
upper ends, taken together, resemble the mouth 
of a pitcher or ewer; from which circumstance '•---- 
their name is derived. Their bases are broad; 
and on their lower surfaces is a cavity, which 
corresponds with the convex edge of the cri- 
coid cartilage, to which they are applied. At these places, a re- 
gular movable articulation is formed, by a capsular ligament 
between each of these cartilages and the cricoid, in consequence 
of which they can be inclined backward or forward, inward or 
outward. 

From the anterior part of each of these cartilages, near the 
base, a tendinous cord passes forward, in a direction which is 
horizontal when the body is erect, to the internal surface of the 
angle of the thyroid. These ligaments are not perfectly parallel 
to each other; for they are nearer before than behind. The 
aperture between them is from two to five lines wide when the 
muscles are not in action ; and this aperturef is the orifice of 
the windpipe : for the exterior space, between these ligaments 
and the circumference of the thyroid, is closed up by membrane 

* Fig. 36. Vertical section of the larynx, h, Os hyoides. t, Thyroid carti- 
lages, cc, Cricoid cartilage, a, Arytenoid cartilage, v, Ventricle of the larynx, 
bounded below by the ligamenta vocales, and above by the superior ligaments of 
the glottis, e, Epiglottis cartilage, g, Ligamentous attachment of the tongue to 
the os hyoides. b, Trachea cut off at the third ring. The lining membrane is 
left out in this section. 

t It forms also the rima gloltidis of the larvnv^- 



EPIGLOTTIS. 441 

and muscle. At a small distance above these ligaments are two 
others, which also pass from the arytenoid to the thyroid carti- 
lages. They are not so tendinous and distinct as the first men- 
tioned, and cannot be drawn so tense by the muscles of the ary- 
tenoid cartilages. They are also situated at a greater distance 
from each other, and thus form a large aperture. 

On the external side of the upper extremity of each of the 
arytenoid cartilages, and nearly in contact with it, is a small 
cartilaginous body, not so large as a grain of wheat, and nearly 
oval in form. These are connected firmly to the arytenoid car- 
tilages, and are called their appendices.* Being in the margin of 
the aperture of the larynx, they have an effect upon its form. 

The arytenoid cartilages are the posterior parts of the larynx: 
the Epiglottis, which has already been mentioned is the anterior. 
When this cartilage is divested of its membrane, it is oval in its 
upper extremity, and rather angular below, terminating in a long 
narrow process, which is like the stalk of a leaf. 

It is firmly attached to the internal surface of the angular 
part of the thyroid by this lower process; and, being placed in a 
perpendicular position, one of its broad surfaces is anterior to- 
wards the tongue, and the other posterior, towards the opening 
of the windpipe. 

It is attached to the os hyoides by dense cellular texture or 
ligament, and to the tongue by those plaits of the membrane of 
the mouth which have been already described. 

It is elastic, but more flexible than the other cartilages ; being 
somewhat different in its structure. Its surface is perforated by 
the orifices of many mucous ducts. 

There is a small space between the lower part of this carti- 
lage, and the upper part of the thyroid and the ligamentous 
membrane passing from it to the os hyoides. In this is a sub- 
stance, which appears to consist of glandular and of adipose mat- 
ter, (see Fig. 36.) It is supposed that some of the orifices on the 
lower part of the epiglottis communicate with this substance. 

— This substance is a collection of mucous glands, called 
glandulcc epiglottidce ; the ducts which arise from them are 

• Tliey are also called Cornicula Laryngis, Tubercles of Santorini. — p. 



442 VENTRICLE OF GALEN OR MORGAGNI.-RIMA GLOTTIDIS. 

twenty or thirty in number, and perforate the epiglottis to throw 
their mucus on the side of the larynx. — 

In the erect position of the body, the epiglottis is situated 
rather higher up than the arytenoid cartilages, and at the dis- 
tance of ten or twelve lines from them. 

The mucous membrane which covers the epiglottis, is reflected 
backwards from the base of the tongue, and is extended from 
each side of it to the arytenoid cartilages, and being continued 
into the cavity of the larynx, as well as upon the general surface 
of the throat, it is necessarily doubled : this doubling forms the 
lateral margins of the orifice of the cavity of the larynx. In 
these folds of the membrane are seen some very delicate mus- 
cular fibres, forming the Aryteno-epiglottideus muscle. 

—The epiglottis maintains its vertical position, partly from its 
own elasticity of structure, and partly from the folds of mucous 
membrane, reflected to it from the tongue, which contain some 
yellow elastic ligamentous fibres. — 

The membrane continues down the cavity of the larvnx, and, 
covering the upper ligaments, penetrates into the vacuity between 
them and the lower ligaments, so as to form a cavity on each 
side of the larynx, opening between the two ligaments, which is 
called the Ventricle of Mm^gagni. The shape of these cavities 
is oblong. Its greatest length extends from behind forward, on 
each side of the opening into the windpipe formed by the two 
lower or principal ligaments; so that when the larynx is re- 
moved from the subject, upon looking into it from above, you per- 
ceive three apertures: one in the middle, formed p- 37 # 
by the two lower ligaments; and one on each 
side of it, between the lower and upper liga- 
ment, which is the orifice of the ventricle of 
Morgagni. 

The aperture between the two lower liga- 
ments is called the Rima Gloltidis, or Chink 
of the Glottis; the upper aperture, formed 
by the fold of the membrane extending "& 7 ' 

* Fig. 37. Front view of the larynx ; plan of its interior cavity, represented by 
the lines a a, b b. Is, Superior ligaments of the glottis, li, Inferior ligaments. 




. . _ h 



GLOTTIS. 443 

from the epiglottis to the arytenoid cartilages, may be termed 
Glottis. 

— The folds of the membrane forming the upper margin of the 
glottis is loose and distensible, and is liable in laryngeal inflam- 
mation to become cedematous and bag out so as to impede re- 
spiration to a great extent, and even produce suffocation. — 

If the windpipe is divided near the larynx, and the larynx in- 
verted, so that the rima glottidis may be examined from below, 
the structure appears still more simple : it resembles a septum 
fixed abruptly in the windpipe, with an aperture in it of the 
figure of the rima glottidis. 

The anterior surface of the two arytenoid cartilages is con- 
cave. This concavity is occupied in each by a glandular 
substance, which lies between the cartilage and the lining mem- 
brane ; and extends itself horizontally, covered by the upper 
ligament of the glottis. The nature of these bodies is not per- 
fectly understood ; but they are supposed to secrete mucus.* 

The membrane which lines the cavity of the glottis being 
continued from the mouth and throat, resembles the membranes 
which invest those parts. In some places, where it is in close 
contact with the cartilages, it appears united with the perichon- 
drium, and acquires more firmness and density. 

The general motions of the larynx are very intelligible to those 
who are acquainted with the muscles which are connected with 
the thyroid cartilage, and which move the os hyoides. They 
take place particularly in deglutition, and in some modifications 
of the voice; and also in vomiting.f 

The motions of the particular cartilages on each other can 
also be well understood, by attending to the origin and insertion 
of the various small muscles connected with them. The most 
important of these muscles are the crico-arytenoidei postici and 

or ligamenta vocales; the space between the two vocal ligaments forms the chink 
of the glottis. All the space above them bounded by the epiglottis cartilage, forms 
the glottis. Ii, Os hyoides. r, Thyroid, c, Cricoid cartilage. 

* They constitute the glandula anjtenoiilca. — r. 

t For an excellent exposition of the uses of the larynx, see Dunglison's Physi- 
ology, 4th edition. — p. 



444 VESSELS AND NERVES OF THE LARYNX. 

laterales, the thyreoarytenoidei, the arytenoidei obliqui, and the 
arytenoideus transversus. The effects of their actions appear to 
be the dilating or contracting the rima glottidis, and relaxing or 
extending the ligaments which form it. 

The arteries of the larynx are derived from two sources, 
namely, the superior thyroid, or laryngeal branch of the ex- 
ternal carotid, and the thyroid branch of the subclavian. 

The nerves of the larynx also come to it in two very different 
directions on each side. It receives two branches from the par 
vagum ; one which leaves that nerve high up in the neck, and is 
called the Superior Laryngeal branch ; and another which pro- 
ceeds from it after it has passed into the cavity of the thorax, 
and is called from its direction the Recurrent. 

— According to M. Blandin, who has rather recently made 
some research upon this subject, the superior laryngeal nerve, is 
distributed chiefly to the mucous membrane and cryptas of the 
larynx, but likewise sends some filaments to the arytenoid and 
crico-thyroid muscles, and others which anastomose with the 
branches of the recurrent. The recurrent supplies all the mus- 
cles of the larynx, with the exception of the crico-thyroid. There 
is still among anatomists some difference of opinion in regard 
to the distribution of these nerves. — 

The extreme irritability of the glottis is unequivocally demonstrated by the 
cough which is excited when a drop of water, or any other mild liquid, or 
a crumb of bread enters it Notwithstanding this, a flexible tube, or 
catheter, has several times been passed into the windpipe through the 
rima glottidis, and been endured by the patient a considerable time. 

The cough, which occurs when these parts are irritated, does not appear to 
arise exclusively from the irritation of the membrane within the glottis ; 
for, if it were so, mucilaginous substances, when swallowed slowly, could 
not suspend it. Their effect in relieving cough is universally known ; 
and as they are only applied to the surface exterior to the glottis, it is evi- 
dent that the irritation of this surface must also produce coughing. 

Several curious experiments have been made to determine the effect of divi- 
ding the different nerves which go to the larynx; by which it appears that 
the recurrent branches supply parts which are essentially necessary to the 
formation of the voice, whilst the laryngeal branches supply parts which 
merely influence its modulation, or tone. See Mr. Haigh ton's Essay on 
this subject: Memoirs of the Medical Society of London, vol. iii. 



THE THYROID GLAND. 445 

The Thyroid Gland, (see Fig. 34, p. 417,) 

May be described here, although a part of it is situated below 
the larynx. 

This body consists of two lobes, which are united at their 
lower extremities by a portion which extends across the anterior 
part of the windpipe. Each lobe generally rises upwards and 
backwards from the second cartilaginous ring of the windpipe 
over the cricoid cartilage and a portion of the thyroid. It lies 
behind the sterno-hyoidei, and sterno-thyroidei muscles. It is of 
a reddish-brown colour, and appears to consist of a granulous 
substance; but its ultimate structure is not understood. It is 
plentifully supplied with blood, and receives two arteries on each 
side: one from the laryngeal branch* of the external carotid: 
and the other from the thyroid branch of the subclavian. 

Notwithstanding this large supply of blood, there is no proof 
that it performs any secretion : for although several respectable 
anatomists have supposed that they discovered excretory ducts 
passing to the windpipe, larynx, or tongue, it is now generally 
agreed that such excretory ducts are not to be found. Several 
instances have, however, occurred, in which air has been forced, 
by violent straining, from the windpipe into the substance of this 
gland.f 

— The two lobes of the thyroid gland, when extended and mea- 
sured from side to side are together about three inches in diameter. 
The lobes extend upwards on the sides of the larynx and down- 
wards on the oesophagus, and lie upon the inner face of, and partly 
covering the primitive carotid artery and internal jugular vein. 
That part of the gland which unites the lobes together, and is 

* The main branch from the external carotid, is now more commonly called su- 
perior thyroid. — p. 

t There are two membranous expansions in the neck which should be noticed 
in its dissection. The first, called Fascia Superficialis, lies immediately beneath 
the skin, may be considered as a continuation of the fascia superficialis abdominis, 
and is strongly connected to the base of the lower jaw, being also spread over the 
parotid gland. It is not very distinct in all subjects. The second is called the 
Fascia Profunda Ccrvicis ; it extends from the larynx and thyroid gland to the 
upper part of the stcrnnm and first ribs; the great vessels, &c. of the superior me- 
diastinum arc placed immediately below it. — h. 
vol. i. 38 



446 STRUCTURE OF THE PHARVNX. 

stretched across the trachea, covering the two or three usually 
and sometimes the seven upper rings of the trachea, is called the 
isthmus of the gland. From the upper surface of the isthmus a 
process of the gland is usually seen extending upwards, on the 
left side over the front surface of the larynx, to be attached by 
ligamentous fibres to the os hyoides. A small muscle called the 
levator gland ulae thyroideae, has been described by Duverney, 
Soemmering and others, running down from the os hyoides in 
front of the larynx to the upper part of the isthmus of the gland. 
According to Professor Horner, its existence is very rare, with 
which opinion my own more limited observation coincides. 
— The lobes of the gland are composed of smaller lobules, and 
the spongy structure of the latter, is filled with a yellowish and 
somewhat oily fluid. Of the uses of this gland nothing positively 
is known. Its importance in the system of the adult cannot be 
great, as its removal by extirpation, which has been many times 
practised, has not appeared to leave any functional lesion in the 
economy. — 

Of the Pharynx. 

The pharynx is a large muscular bag, which forms the great 
cavity behind the nose and mouth that terminates in the oeso- 
phagus. 

It has been compared to a funnel, of which the oesophagus is 
the pipe; but it differs from a funnel in this respect, that it is in- 
complete in front, at the part occupied by the nose and mouth 
and larynx. 

It is connected above, to the cuneiform process of the occi- 
pital bone, to the pterygoid processes of the sphenoidal, and to 
both the upper and lower maxillary bones. It is in contact with 
the cervical vertebrae behind; and, opposite to the cricoid carti- 
lage, it terminates in the oesophagus. 

If the pharynx and oesophagus be carefully dissected and de- 
tached from the vertebrae, preserving the connexion of the 
pharynx with the head, and the head then be separated from the 
body, by dividing the articulation of the atlas and the os occipitis, 
and cutting through the soft parts below the larynx, the resem- 
blance to a funnel will be ve ' 



STRUCTURE OF THE PHARYNX. 447 

III this situation, if an incision be made from above down- 
wards through the whole extent of the posterior part of the 
pharynx, the communication of the nose, mouth, and windpipe, 
with this cavity, will be seen from behind at one view. 

The openings into the nose, or the posterior nares, appear up- 
permost. Their figure is irregularly oval, or oblong ; they are 
separated from each other by a thin partition, the vomer. Im- 
mediately behind, on the external side of each of these orifices, 
is the Eustachian tube. (See Fig. 34, p. 417.) 

The soft palate will appear extending from the lower boun- 
dary of the posterior nares, obliquely backwards and downwards, 
so as nearly to close the passage into the mouth. The uvula 
hangs from it : and, on each side of the uvula, the edge of the 
palate is regularly concave. 

Below the palate, in the isthmus of the fauces, are the ridges 
or half arches, and the tonsils between them. The half arch 
which presents first, in this view, runs obliquely downward and 
backward, and not parallel to the other. 

Close to the root of the tongue is the epiglottis erect; and, 
immediately adjoining it, is an aperture large enough to admit 
the end of a middle-sized finger. This aperture is widest at the 
extremity next to the epiglottis, and rather narrower at the other 
extremity: it is the glottis or opening of the windpipe. When 
the larynx is elevated, the epiglottis can be readily depressed so 
as to cover it completely. 

The extremities of the arytenoid cartilages, and their appen- 
dices, may be recognised at the posterior edge of the glottis. 
At a short distance below this edge, the oesophagus begins. 

The Pharynx is composed of the membrane continued from 
the nose and mouth internally, and of a stratum of muscular 
fibres externally. The internal membrane is very soft and flexible 
and perforated by many muciferous ducts. The surface which 
it forms is rather rough, owing to the mucous glands which it 
covers. It has a red colour, but not so deep as that of some 
other parts. It is connected to the muscular stratum by a loose 
cellular membrane. 

The muscular coat consists of three different portions, which 



448 CONSTRICTOR MUSCLES OF THE PHARYNX. ■ 

are considered as so many distinct muscles. They are called the 
superior, middle, and inferior constrictor muscles of the pharynx. 
The fibres of each of these muscles originate on each side, and 
run in an oblique direction to meet in the middle, thus forming 
the posterior external surface of the dissected pharynx. 

The fibres of the upper muscles originate from the cuneiform 
process of the occipital bone, from the pterygoid processes of the 
os sphenoides, and from the upper and lower jaws, near the last 
dentes molares, on each side. They unite in a middle line in the 
back of the pharynx. 

The fibres of the middle muscles originate principally from the 
lateral parts of the os hyoides, and from the ligaments which 
connect that bone to the thyroid cartilage. The superior fibres 
run obliquely upwards, so as to cover a part of the first men- 
tioned muscle, and terminate in the cuneiform process of the 
occipital bone; while the other fibres unite with those of the 
opposite side in the middle line. 

The fibres of the lower muscles arise from the thyroid and the 
cricoid cartilages, and terminate also in the middle line : those 
which are superior, running obliquely upwards; the inferior, 
nearly in a transverse direction. 

It is obvious, from the origin and insertion of these fibres, that 
the pharynx must have the power of contracting its dimensions 
in every respect; and, particularly, that its diameter may be 
lessened at any place, and that the whole may be drawn upwards. 



PART VI. 
OF THE THORAX. 

Before the thorax is described, it will be in order to consider 
the 

Mammas, ; 

Or those glandular bodies situated on the anterior part of it. 
which, in females, are destined to the secretion of milk. 

These glands lie between the skin and the pectoral muscles, 
and are attached to the surfaces of those muscles by cellular 
membrane. 

They are of a circular form ; and consist of a whitish firm 
substance, divisible into small masses or lobes, which are com- 
posed of smaller portions or lobuli. Between these glandular 
portions, a great deal of adipose matter is so diffused, that it 
constitutes a considerable part of the bulk of the mammas. 

The gland, however, varies greatly in thickness in the same 
person at different periods of life. 

The mamma) become much enlarged about the age of pu- 
berty. They are also very large during pregnancy and lacta- 
tion ; but after the period of child-bearing they diminish consider- 
ably. They are supplied with blood by the external and inter- 
nal mammary arteries, the branches of which enter them irre- 
gularly in several different places. 

The veins correspond with the arteries. 

From the small glandular portions that compose the mamma, 
tine excretory tubes arise, which unite together and form the 
great lactiferous ducts of the gland. These ducts proceed in a 
radiated manner from the circumference to the centre, and ter- 
minate on the surface of the nipple.* 

* Described in the 10th century, by Charles Etienne, Vesalius and Posthius, 
but their uses were unknown. — h. 

38* 



450 



MAMMAE. 



They are commonly about fifteen in number, and vary con- 
siderably in size : the largest of them being more than one-sixth 
of an inch in diameter.* 

They can be very readily injected by the orifices of the nip- 
ple, from a pipe filled with mercury, in subjects who have died 
during lactation or pregnancy ; but they are very small in sub- 
jects of a different description. 

It has been asserted by respectable anatomists, that these ducts 
communicate freely with each other; but they do not appear 
to do so ; each duct 

seems to be connect- Fig. 38.f 

ed with its proper 
branches only.J 

Haller appears to 
have entertained the 
remarkable sentiment, 
that some of the ducts 
originate in the adi- 
pose matter about the 
gland, as well as in 
the glandular sub- 
stance.§ 

The papilla, or nip- 
ple, in which these ducts terminate, is in the centre of the mam- 
ma: it consists of a firm elastic substance, and is nearly cylin- 

* These ducts vary in number in different individuals, from fifteen to twenty. — p. 

t Fig. 38, is a vertical section of the mammary gland of a young female who 
died during lactation. The ducts were injected with wax, and two dissected ou* 
their full length to their origin in the lobules of the gland. 2, 2, Base of the nip- 
ple. 3, 3, 3, Lactiferous ducts cut off at the base of the nipple. 4, 4, The top of 
the ducts which exhibited their whole length. 5, 5, Sinuses formed by these ducts 
at the base of the nipple. 6, 6, 6, 6, Branches of these duets running to the lo- 
bules. 7, 7, 7, 7, 7, The lobules separated from each other. 8, 8, The orifices of 
these ducts on the top of the nipple. 

X See Edinburgh Medical Commentaries, vol. i. p. 31. — A paper by Meckel. — h. 

§ Elementa Physiologiae, Tom. 7, Pars II. page 7. — In the adipose matter 
about the gland, the lactiferous tubes (ducti galactophori) appear to communicate 
with the absorbent vessels. In injecting the gland with mercury, I have frequently 
found the metal to pass off from the ducts along the absorbent vessels. — p. 




LACTIFEROUS DUCTS. az% 

drical in form. It is rendered tumid by irritation, and by cer- 
tain emotions. 

The lactiferous ducts terminate upon its extremity. When it 
is elongated they can freely discharge their contents; but when 
it contracts, this discharge is impeded. The skin immediately 
around the nipple is of a bright red colour in virgins of mature 
age. In pregnant women it is sometimes almost black ; and in 
women who have borne children it is often brownish. It abounds 
with sebaceous glands, which form small eminences on its sur- 
face. 

This gland exists in males, although it is very small. In boys, 
soon after birth, it has often been known to tumefy, and become 
very painful, in consequence of the secretion and accumulation 
of a whitish fluid, which can be discharged by pressure. It also 
sometimes swells and is painful, in males at the age of puberty. 

There have been some instances in which it has secreted milk 
in adult males; and a few instances also in which it has been af- 
fected with cancer, in the same sex. 

The mamma is plentifully supplied with absorbent vessels, 
which pass from it to the lymphatic glands in the axilla. 

Its nerves are principally derived from the great plexus formed 
by the nerves of the arm. 

—The skin covering the mammary gland, is exceedingly thin, 
delicate and vascular, and that of the nipple and areola, more 
delicate and sensitive than any other portion. 
—Each lactiferous duct by its branching and convolutions, forms 
a distinct lobule of the gland, and terminates in a series of vas- 
cular granules* about the size of millet seed, which are readily 
distinguished from each other in individuals who have died dur- 
ing lactation. The lobules of the gland vary in size, which, in 
subjects where the subcutaneous matter is not abundant, gives a 
feeling of unevenness or roughness to the gland. 
—There are no valves in the lactiferous tubes— 

• Histoire de la Generation, par Grimaud de Caux et Martin Saint-An ff e 4to 
Paris, 1837.— p. 6 ' 



452 CAVITY OF THE THORAX. 

CHAPTER XV. 

OF THE GENERAL CAVITY OF THE THORAX. 

Of the Form of the Cavity of the Thorax. 

The osseous structure of the thorax is described in page 136. 
The cavity is completed by the intercostal muscles, which close 
the vacuities between the ribs ; and by the diaphragm, which 
fill up the whole space included within its lower margin. 

If we except the apertures of the diaphragm, which are com- 
pletely occupied by the aorta, the vena cava, and the oesopha- 
gus, &c, the only outlet of this cavity is above : it is formed by 
the upper ribs, the first dorsal vertebra, and the sternum. The 
figure of this aperture is between that of the circle and the oval ; 
but it is made irregular by the vertebrae, and by the upper edge 
of the sternum. 

When the superior extremities and the muscles appropriated 
to them are removed, the external figure of the thorax is coni- 
cal ; but the cavity formed by it is considerably influenced by 
the spine, which protrudes into it ; while the ribs, as they pro- 
ceed from the spine, curve backwards, and thus increase its pro- 
minency of the cavity. 

The diaphragm has a great effect upon the figure of the 
cavity of the thorax. It protrudes into it from below, with a 
convexity of such form that it has been compared to an inverted 
bowl ; so that although it arises from the lower margin of the 
thorax, the central parts of it are nearly as high as the fourth 
rib. 

The position of the diaphragm is also oblique. The anterior 
portion of its margin, being connected to the seventh and eighth 
ribs, is much higher than the posterior portion, which is attached 
to the eleventh and twelfth. 

In consequence of the figure and position of the diaphragm. 



PLEURAE. 453 

the form of the cavity of the thorax resembles that of the hoof 
of the ox when its posterior part is presented forwards. 

Of the Arrangement of the Pleurce. 

The thorax contains the two lungs and heart, as well as se- 
veral very important parts of smaller size. 

The lungs occupy the greatest part of the cavity ; and to 
each of them is appointed a complete sac, called Pleura, which 
is so arranged that it covers the surface of the lungs, and is con- 
tinued from it to the contiguous surface of the thorax, which it 
lines. After covering the lung, it is extended from it to the spine 
posteriorly : so that in tracing the pleura in a circular direction, 
if you begin at the sternum, it proceeds on the inside of the ribs, 
to the spine ; at the spine it leaves the surface of the thorax, and 
proceeds directly forwards towards the sternum. In its course 
from the spine to the sternum, it soon meets with the great branch 
of the windpipe and blood-vessels, which go to the lung: it 
continues on these vessels and round the lung until it arrives at 
the anterior side of the vessels, when it again proceeds forwards 
until it arrives at the sternum. Each sac being arranged in the 
same way, there is a part of each extended from the spine to the 
sternum. These two laminae form the great vertical septum of 
the thorax, called Mediastinum. They are situated at some dis- 
tance from each other; and the heart, with its investing mem- 
brane or pericardium, is placed between them. 

The pericardium is also a complete sac or bladder, which, 
after covering perfectly the surface of the heart, is extended 
from it so as to form a sac, which lies loose about it, and appears 
to contain it. This loose portion adheres to those parts of the 
laminse of the mediastinum with which it is contiguous ; and 
thus three chambers are formed within the cavity of the thorax : 
one for each lung, and one for the heart. 

The two lamina of the pleura, which constitute the mediasti- 
num, are at different distances from each other, in different 
places. At the upper part of the thorax, they approach each other 
from the internal edges of the first ribs ; and as these include a 



454 MEDIASTINUM. 

space which is nearly circular, the vacuity between these lamina 
is necessarily of that form, at its commencement above. 

Here, therefore, is a space between them above, which is oc- 
cupied by the transverse vein that carries the blood of the left 
subclavian and the left internal jugular to the superior cava ; by 
the trachea; by the oesophagus; and by the subclavian and 
carotid arteries, as they rise from the curve of the aorta. This 
space is bounded below by the above mentioned curve of the 
aorta. 

The heart and pericardium are so placed that there is a small 
distance between them and the sternum : in this space the two 
lamina of the mediastinum are very near to each other; and 
cellular substance intervenes between them. This portion of 
the mediastinum is called the Anterior Mediastinum.* 

Posteriorly, the heart and pericardium are also at a small dis- 
tance from the spine ; and here the lamina of the mediastinum 
are at a greater distance from each other, and form a long nar- 
row cavity which extends down the thorax in front of the ver- 
tebrae: this is called the Posterior Mediastinum. It contains a 
considerable portion of the aorta as it descends from its curve, 
the oesophagus, the thoracic duct, and the vena azygos. The 
aorta is in contact with the left lamen, and can often be seen 
through it when the left lung is lifted up. 

The oesophagus is in contact with the right lamen ; in its pro- 
gress downwards, it inclines to the left side and is advanced be- 
fore the aorta. 

The vena azygos appears posterior to the oesophagus ; it pro- 
ceeds upwards until it is as high as the right branch of the wind- 
pipe : here it bends forward, round that branch, and opens into 
the superior cava, before that vein opens into the right auricle. 

The thoracic duct proceeds upwards from below, lying in 

* This mediastinum, being placed in front of the longitudinal diameter of the 
pericardium is found at its lower part inolined to the left of the middle line. 
The cellular tissue between its layers, communicates indirectly with the cellular 
tissue on the outer side of the peritoneum, in the notch formed by the origin of 
the greater muscle of the diaphragm, under the xiphoid appendix of the sternum. 
By this channel, abscesses of the anterior mediastinum, may make their way ex- 
ternally upon the abdomen. — p. 



PREPARATION OF THE THORAX. 455 

the space between the aorta and the vena azygos, until the be- 
ginning of the curve of the aorta, when it inclines to the left, 
proceeding towards the place of its termination. 

— The anterior and posterior mediastinae are formed as is 
shown above, by the layers of the pleura, between the sternum 
and pericardium, and between the pericardium and spine. But 
the pericardium does not extend the whole length of the thoracic 
cavity; it terminates about two inches short of the top of 
the sternum, and at this part, there being nothing interposed 
to divide the layers into an anterior and posterior portion, they 
pass directly from the vertebra to the sternum, and constitute 
what is called the Superior Mediastinum. The two layers 
constituting this, continuous below with the anterior and superior 
mediastinas, and each lining the upper margin of the first rib, so 
as to form a conical pouch projecting a slight distance above the 
middle of the clavicle, constitute a triangular cavity, the base of 
which is upwards, and corresponds to the root of the neck. 
This cavity contains the thymus gland, the arteria innominata, 
the primitive carotid and subclavian of the left side, the superior 
vena cava, the trachea, oesophagus, and par vagum nerve. 
— The sympathetic nerve is not contained in this mediastinum ; it 
passes a little to the outside of the posterior external angle of 
it.— 

The formation of the mediastinum, and the arrangement of the pleura, as 
well as the connexion of these membranes with the parts contained in 
the thorax, may be studied advantageously, after the subject has been pre- 
pared in the manner now to be described. 

Take away, from each side, the five ribs which are situated between the 
first and last true ribs, by separating their cartilages from the sternum, 
and their heads from the spine; so that the great cavities of the thorax 
may be laid open. 

The precise course of the mediastinum is thus rendered obvious; and the 
sternum may now be divided with a saw throughout its whole length in 
the same direction; so that the division of the bone may correspond with 
the space between the lamina of the mediastinum. 

rSeparatc the portion of the sternum cautiously, so as to avoid lacerating the 
lamina of mediastinum; and to keep them separate., while the trachea is 
dissected from the neck into the cavity of the thorax; the great trans- 
verse vein and the descending cava are dissected to the pericardium; and 



456 PREPARATION OF THE THORAX. 

the left carotid artery, with the right subclavian and carotid, are dissected 
to the curve of the aorta, taking care not to destroy the lamina of the 
mediastinum. 

After this preparation the upper space between the lamina of the mediasti- 
num can be examined, and the relative situation of the trachea and 
the great vessels in it can be understood. The anterior mediastinum 
can also be studied: the root of each lung, or its connexion with the me- 
diastinum, may be seen perfectly; and the precise situation of the lung, 
in its proper cavity, may be well conceived. 

After this, while the portions of the sternum are separated, the pericardium 
may be opened, and the heart brought into view: the attachment of the 
pericardium, and to the mediastinum, and to the diaphragm, may be seen 
with advantage in this situation. The portions of the sternum may now 
be detached from the ribs, with which they remain connected ; and fur- 
ther dissection may be performed to examine the posterior mediastinum 
and its contents, and the parts which constitute the roots of the lungs. 



OF THE PERICARDIUM. 457 



CHAPTER XVI. 

OF THE HEART AND PERICARDIUM, AND THE GREAT VESSELS CON- 
NECTED WITH THE HEART. 

Of the Pericardium. 

The heart is enclosed by a membranous sac, which, upon a 
superficial view, seems only connected with its great vessels. 

— The whole of the organ lays unattached in the cavity of 
the sac, except, by the arteries and veins connected with its base. 
The sac is in fact composed of two layers, one external and 
fibrous, and one internal and serous ; the latter of these not only 
lines the inner face of the outer membrane, but is reflected like 
other serous membranes, over the roots of the vessels placed 
in the pericardium, and over the whole of the outer surface 
of the heart itself. This internal serous lining is very thin 
and delicate, and can only be raised in small shreds, either 
from the outer layer of the pericardium, or from the heart; 
except at the base of the latter organ, where, in females, it is 
usually, and in males, frequently, separated from the muscular 
tissue, by some sub-serous fatty matter. — 

If it were dissected from the heart, without laceration or 
wounding, it would be an entire sac. 

The pericardium, thus arranged, is placed between the two 
lamina of the mediastinum, and adheres firmly to them where 
they are contiguous to it; it also adheres firmly to the diaphragm 
below, and thus preserves the heart in its proper position. 

The figure of the pericardium, when it is distended, is some- 
what conical; the base being on the diaphragm. The cavity 
formed by it is larger than the heart after death, but it is pro- 
bable, that the heart nearly fills it during life; for when this 
organ is distended by injection, it often occupies the whole cavity 
of the pericardium. 

— The attachment of the pericardium to the diaphragm, is 
vol. 1. 39 



458 PERICARDIUM. 

exactly over the cordiform tendon of the latter. The French 
anatomists have erroneously considered the fibrous layer of the 
pericardium, as a mere reflection of the tendon upwards. By 
separating them with a knife, we find, they are united by a short 
cellular tissue, which is densest and strongest at the periphery of 
their junction. The sides of the pericardium are covered in 
part by the pleura, which gives the sac the appearance of being 
formed by three tunics. 

— Underneath the pleural lining, is found the phrenic nerve, and 
in fat subjects, a good deal of adipose matter. — 

The pericardium is composed of two lamina, the internal of 
which covers the heart, as has been already described ; while 
the external merely extends over the loose portion of the other, 
and blends itself with the mediastinum, where that membrane 
invests the great vessels. 

— Its principal attachment or termination above, is upon the 
arteries and veins entering the heart, (with the exception of the 
vena cava inferior,) over which it sends tubular prolongations, 
which gradually blend with their external coats. Between these 
prolongations on the inside of the sac, hollow pouches are neces- 
sarily left, which are called the cornua of the pericardium. 
— The fibrous layer of the pericardium resembles in structure 
and appearance, the dura mater of the brain. 
— The arteries of the pericardium are very small ; they are de- 
rived from the phrenic, bronchial, aesophageal, internal mammary 
arteries, and from the aorta itself. Its veins terminate in the 
vena azysros. Its nerves are few and small, and originate from 
the cardiac plexus. — 

The internal surface of the pericardium is very smooth and po- 
lished ; and in the living subject is constantly moistened with a fluid 
which is probably effused from the exhalent vessels on its surface. 
The quantity of this fluid does not commonly exceed two 
drachms; but in cases of disease it sometimes amounts to many 
ounces.* It is naturally transparent, but slightly tinged with red 

* The pericardium has been so distended, by effusion in dropsy, that it has 
formed a tumour, protruding on the neck from y.nder the sternum. This tumour 
had a strong pulsating motion. It disappeared completely when the other hydropic 
symptoms were relieved. 



OF THE HEART. 



459 



in children, and yellow in old persons. It is often slightly tinged 
with red in persons who have died by violence. 

Of the Heart. 

The great organ of the circulation consists of muscular fibres, 
which are so arranged that they give it a conical form, and 
compose four distinct cavities within it. 

Two of these cavities, which are called Auricles, receive the 
contents of the veins; the other two communicate with the ar- 
teries, and are called Ventricles. 

The auricles form the basis of the cone ; the ventricles the 
body and apex. 

The structure of the auricles is much less firm than that of the 
ventricles, and consists of a smaller proportion of muscular 
fibres. They appear like appendages of the heart, while the 
ventricles compose the body of the viscus. 

The ventricles are very thick, and are composed of muscular 
fibres closely compacted. 

The figure of the heart is not regularly conical ; for a portion 
of it, extending from the apex to the base, is flattened ; and in its 
natural position, this flat part of the surface is downwards. 

It is placed obliquely in the body ; so that its base presents 
backward and to the right, and its apex forward and to the left. 
Notwithstanding this obliquity, the terms right and left are 
applied to the different sides of the heart, and to the different 
auricles and ventricles ; although they might, with equal pro- 
priety, be called anterior and posterior. 

The two great veins called Vena Cava, which bring the blood 
from every part of the body, open into the right auricle from 
above and below ; the right auricle opens into the right ventricle; 
and from this ventricle arises the artery denominated Pulmonary, 
which passes to the lungs. 

The Pulmonary veins, which bring back the blood from the 

lungs, open into the left auricle ; this auricle opens into the left 

ventricle ; and from this ventricle proceeds the Aorta, or great 

artery, which carries blood to every part of the body. 

The heart is preserved in its position, 1st, by the venae cavre 



460 



RIGHT AURICLE. 



which are connected to all the parts to which they are contigu- 
ous in their course; 2d, by the vessels which pass between it 
and the lungs, which are retained in a particular position by the 
mediastinum ; 3d, by the aorta, which is attached to the medias- 
tinum in its course downwards, after making its great curve ; 
and 4th, by the pericardium, which is attached to the great 
vessels and to the mediastinum. By these different modes the 
basis of the heart is fixed, while its body and apex are perfectly 
free from attachment, and only contiguous to the pericardium. 

The external surface of the heart, being formed by the serous 
layer of the pericardium, is very smooth : under this surface a 
large quantity of fat is often found. 

The two auricles are contiguous to each other at the base, and 
are separated by a partition which is common to both. 

The Right Auricle originates from the junction of the two 



Fig. 39.* 
ft ~h ft 




vense cavse. These veins are 
united at some distance behind 
the right ventricle,f and are di- 
lated anteriorly into a sac or 
pouch, which is called the Sinus, 
and extends to the right ventricle, 
to which it is united.J 

The upper part of this pouch, 
or sinus, forms a point with in- 
dented edges, which is detached 
from the ventricle, but lies loose 
on the right side of the aorta. 
This point has some resem- 
blance to the ear of a dog, from 



* Fig. 39. — Longitudinal section of the heart, showing its cavities, b, Right 
ventricle, c, Septum ventriculorum. d, Right auricle, e, left auricle. /, Sec- 
tion of the mitral valves, g, Section of tricuspid valves. A, Arch of aorta. A, de- 
scending aorta, i, i, Vena cava superior and inferior, k, k, Right and left 
branches of the pulmonary artery. I, I, Pulmonary veins. 

t In this description the heart is supposed to be in its natural position. 

X At the place of junction of these veins there is a projection, indistinctly seen 
in man, but very manifest in some of the larger mammalia, called tuberculum 
Loweri. — p. 



RIGHT AURICLE 461 

which circumstance the whole cavity has been called auricle ; 
but by many persons the cavity is considered as consisting of 
two portions: the Auricle, strictly speaking; and the Sinus Ve- 
nosus, above described : they however form but one cavity. 

This portion of the heart, or Right Auricle, is of an irregular 
oblong figure. In its posterior surface, it is indented ; for the 
direction of the two cavse, at their junction, is not precisely the 
same ; but they form an angle, which causes this indentation. 
The anterior portion of the auricle, or that which appears like a 
pouch between the ventricle and the veins, is different in its 
structure from the posterior part, which is strictly a portion of 
the veins. It consists simply of muscular fibres, which are ar- 
ranged in fasciculi that cover the whole internal surface: this is 
also the case with the point, or that part which is strictly called 
auricle. 

These fasciculi are denominated Musculi Pectinati, from their 
resemblance to the teeth of a comb. 

That part of the internal surface, which is formed by the 
septum is smooth, and the whole is covered by a delicate mem- 
brane. 

On the surface of the septum, below the middle, is an oval de- 
pression, which has a thick edge or margin : this is called the 
Fossa Ovalis* In the foetal heart, it was the Foramen Ovale, 
or aperture which forms the communication between the two 
auricles. 

Near this fossa is a large semilunar plait, or valve, with its 
points and concave edge uppermost, and convex edge down- 
wards. It was described by Eustachius, and therefore, is called 
the Valve of Eustachius. 

— It commences at the lower surface of the opening of the 
inferior vena cava, and runs forwards to terminate below the 
fossa ovalis. It served in the foetus to obstruct the passage of 
the venous blood from the right auricle into the right ventricle, 
and to direct it in a great measure through the foramen ovale. — 

Anterior to this valve, and near the union of the auricle and 

• The thick edge or margin is spoken of as the annulus ovalis. — p, 
39* 



462 RIGHT VENTRICLE. 

ventricle, is the orifice of the proper vein of the heart, or the 
coronary vein. This orifice is covered by another semilunar 
valve, which is sometimes reticulated.* 

The aperture, which forms the communication between the 
right auricle and right ventricle, is about an inch in diameter, 
and is called ostium venosum. From its whole margin arises a 
valvular ring, or duplicature of the membrane lining the surface: 
this circular valve is divided into three angular portions, which 
are called Valvules Tricuspides. From their margins proceed a 
great number of fine tendinous threads, which are connected to 
a number of distinct portions of muscular substance, which arise 
from the ventricle. 

The Right Ventricle, when examined separately from the 
other parts of the heart, is rather triangular in its figure. It is 
composed entirely of muscular fibres closely compacted; and is 
much thicker than the auricle, although not so thick as the other 
ventricle. Its internal surface is composed of bundles or co- 
lumns of fleshy fibres, which are of various thickness and length. 
Some of these columns (columnce earned) arise from the ven- 
tricle, and are connected with the tendinous threads, {chorda 
tendinece,) which are attached to the margin of the tricuspid 
valves: the direction of them is from the apex of the heart 
towards the base. Others of the columns arise from one part of 
the surface of the ventricle, and are inserted into another part. 
A third species are attached to the ventricle throughout their 
whole length, forming ridges or eminences on it. The columns 
of the two last described species are very numerous. They pre- 
sent an elegant reticulated surface when the ventricle is laid 
open, and appear also to occupy a considerable portion of the 
cavity of the heart, which some of them run across in every di- 
rection near the apex. They are all covered by a membrane 
continued from the auricle and the tricuspid valves; but this 
membrane appears more delicate and transparent in tiie ventri- 
cle than it is in the auricle. 

* The orifice is called the foramen Thebesii, and the valve, valvula Thebesii, 
from the anatomist who first described them. 

There are several other orifices in the neighbourhood of the foramen of Thebe- 
sius, by which some of the lesser coronary veins discharge into the right auricle. — p. 



RIGHT VENTRICLE. 453 

— This is called the internal serous, or endo-cardial lining 
membrane of the heart. On the right side it is continuous with 
that of the veins and pulmonary artery, on the left with the aorta 
and pulmonary veins. It is extremely thin, smooth, and transpa- 
rent, covers all the interior surface of the cavities of the heart, 
and by being thrown into folds with some fibrous matter inter- 
posed between the layers to increase their strength, constitutes 
the valves. — 

A portion of the internal surface of the ventricle, which is to 
the left, is much smoother and less fasciculated than the rest : it 
leads to the orifice of the pulmonary artery, which arises from 
it near the basis of the ventricle. This artery is very conspicu- 
ous, externally, at the basis of the heart. 

It is very evident, upon the first inspection of the heart, that 
the valvulas tricuspides will permit the blood to flow from the 
auricle to the ventricle; but must rise and close the orifice, and 
thereby prevent its passage back again, when the ventricle con- 
tracts. 

The use of the tendinous threads, which connect the valves to 
the fleshy columns, is also very evident ; the valve is supported 
by this connexion, and prevented from yielding to the pressure 
and opening a passage into the auricle. The blood, therefore, 
upon the contraction of the ventricle, is necessarily forced into 
the pulmonary artery ; the passage to which is now perfectly 
free. Into this artery the membrane lining the ventricle seems 
continued; but immediately within the orifice of the artery, it is 
formed into three semicircular folds, each of which adheres to 
the surface of the artery by its circumference, while the edge 
constituting its diameter is loose. In the middle of this loose 
edge is a small firm tubercle, called Corpusculum Arantii,* 
which adds to the strength of the valve. Each of these valves, 
by its connexion with the artery, forms a sack or pocket, the 
orifice of which opens forward towards the course of the artery, 
and the bottom of it presents towards the ventricle. Blood will, 
therefore, pass from the ventricle in the artery, and along it 

• After Arantius, a professor at Bologna, who first described it. 



4G4 LEFT AURICLE. 

without filling these sacks; and, on the contrary, in this course, 
will compress them and keep them empty. If it moves in the 
artery towards the heart, it will necessarily fill these sacks, and 
press the semicircular portions, from the sides of the artery, 
against each other ; by this means a partition or septum, con- 
sisting of three portions, will be formed between the artery and 
the heart, which will always exist when the artery compresses, 
(or acts upon,) its contents. It is demonstrable, by injecting 
wax into the artery, in a retrograde direction, that these valves 
do not form a flat septum, but one which is convex towards the 
heart, and concave towards the artery ; and that this convexity 
is composed of three distinct parts, each of which is convex. 
At the place where these valves are fixed, the artery bulges out 
when distended by a retrograde injection. The enlargements 
thus produced are called the Sinuses of Valsalva, after the ana- 
tomist who first described them. The valves are called Semi- 
lunar — and, although they are formed by a very thin membrane, 
they are very strong. 

The Left Auricle is situated on the left side of the basis of the 
heart. It originates from the junction of the four pulmonary 
veins ; two of which come from each side of the thorax, and 
appear to form a large part of it. It is nearly of a cubic form ; 
but has also an angular portion, which constitutes the proper 
auricle, that proceeds from the upper and left part of the cavity, 
and is situated on the left side of the pulmonary artery. 

This auricle is lined by a small membrane, from which the 
valves between it and the ventricle originate ; but it has no 
fleshy columns or musculi pectinati, except in the angular pro- 
cess properly called auricle. 

These valves and the orifice communicating with the ventri- 
cle, resemble those which have been already described between 
the right auricle and ventricle ; but with this difference, that the 
valvular ring is divided into two portions only, instead of three, 
which are called Valvules Mitrales.* The tendinous threads, 
which are connected to the muscular columns, are also attached 
to these valves, as in the case of the right auricle. 

* From a resemblance in shape to the mitre or bishop's cap. — p. 



LEFT VENTRICLE. 465 

These valves admit the passage of blood from the auricle 
into the ventricle, but completely prevent its return when the 
ventricle contracts. One of them is so situated that it covers 
the mouth of the aorta while the blood is flowing into the ventri- 
cle, and leaves that orifice open when the ventricle contracts, 
and the passage to the auricle is closed. 

The Left Ventricle is situated posteriorly, and to the left of the 
Right Ventricle. Its figure is different, for it is rather conical, 
and it is also longer. 

The internal surface of this ventricle resembles that of the 
right ventricle: but the columnse carnese are stronger and 
larger. 

On the right side of this ventricle is the mouth of the aorta. 
The surface of the ventricle near this opening is smooth and po- 
lished, to facilitate the passage of the blood. 

The mouth of the aorta is furnished with three semilunar 
valves, after the manner of the pulmonary artery, but the former 
are stronger; the corpuscula Arantii are better developed in 
them. Indeed, Mr. Hunter does not admit of their existence in 
the pulmonary artery. The sinuses of Valsalva are about the 
same size in both arteries. 

The cavity of this ventricle is supposed to be smaller than 
that of the right: but the amount of the difference has not been 
accurately ascertained. 

This ventricle must have much more force than the right, as its 
parietes are so much thicker. Their thickness often exceeds 

half an inch. 

The difference in the strength of the two ventricles probably 
corresponds with the difference between the extent of the pul- 
monary artery and the aorta. 

The* thickness of the septum between the ventricles is thicker 
than the sides of the parietes of the right ventricle, and less 
thick than those of the left. 

The muscular fibres of the heart are generally less florid than 
those of the voluntary muscles; they are also more closely 
compacted together. The direction of many of them is oblique 
or spiral ; but this general arrangement is very intricate : it is 



466 FIBRES OF THE HEART. 

such, however, that the cavities of the heart are lessened, and 
probably completely obliterated, by the contraction of these 
fibres.* 

— The muscular fibres of the heart have been carefully stu- 
died by Wolf and Malpighi, and more recently still, by Gerdy.f 
According to this latter anatomist, there is a fibrous zone or gir- 
dle formed around each auricle and arterial orifice of the heart, 
which zones are connected with each other and with the valves. 
From these zones originate all the muscular fibres of the heart. 
Some which run upwards and turn in every direction round 
the auricles, and form loops, the extremities of which are in- 
serted on the opposite sides of the zone. Others which run 
downwards and embrace the ventricles, and are also inserted on 
the opposite sides of the same zone, or that which surrounds the 
orifices of the aorta or pulmonary artery. The structure of the 
ventricular fibres is most complicated. They are first superfi- 
cially placed, and as they make their spiral turns, sink deep into 
the substance of the heart, somewhat like the contours of a leaf 
of paper rolled into jhe form of a cone. They consist of fibres 
proper to each ventricle, and fibres common to both. The 
former, after arising from the zone, turn spirally around the axis 
of the ventricle, so as to form many times the figure of 8, and 
coming upon the anterior face of the same side, terminate upon 
the zone surrounding the arterial orifice. The fibres common 
to the ventricles are of two kinds — superficial and deep-seated. 
The superficial are divided into anterior and posterior. The an- 
terior arising from the anterior part of the arterial and auricular 
zones, run obliquely downwards and to the left, converging to- 
wards the apex of the heart ; these are rolled around the axis of 
the left ventricle, and dip inwards to terminate in, or form the 
columnas carnese. The superficial part of this order of fibres, 
is common to both ventricles ; the deep-seated part belongs to 
the left only. The posterior superficial fibres arise behind from 

* Mr. Home has given a precise description of the muscular fibres of the heart 
in his Croonian Lecture. London Philosophical Transactions for 1795, part I 
page 215. 

t Journal Complementaire du Diet, des Scienc. Med. torn. ix. p. 97. — p. 



CORONARY VESSELS. 467 

the auricular zones only, and run downwards, so as to embrace 
the right border of the heart, come in front of the heart, and op- 
posite to the septum ventriculorum, dip under the anterior super- 
ficial fibres, wind round the axis of the right ventricle and ter- 
minate in its columnar carnese. These also in part only, are com- 
mon to both ventricles. 

— The deep-seated fibres form the internal part of the walls of 
the right ventricle. They arise from the fibrous zones of the 
right side. The anterior portion of these fibres runs obliquely 
downwards, and backwards to the septum ; the posterior and in- 
ternal, pass at once into the septum, roll themselves round the 
left ventricle and are lost amidst the other fibres. Thus it ap- 
pears, that by removing the superficial layer of the common stra- 
tum, the heart may be divided into lateral halves, each consist- 
ing of two muscular sacs, an auricle and ventricle, adjoined to 
those of the opposite side in the middle line. — 

The external surface of the heart is covered by that portion 
of the pericardium which adheres to it. Adipose matter is often 
deposited between this membrane and the muscular surface ; be- 
ing distributed irregularly in various places. 

This membrane is continued from the surface of the ventricles 
over that of the auricles. When it is dissected off from the 
place of their junction, these surfaces appear very distinct from 
each other. 

The proper blood-vessels of the heart appear to be arranged in 
conformity to the general laws of the circulation, and are very 
conspicuous on the surface. There are two arteries which arise 
from the aorta immediately after it leaves the heart, so that their 
orifices are covered by two of the semilunar valves. One of 
these pass from the aorta between the pulmonary artery and the 
right auricle, and continues in a circular course in the groove 
between the right auricle and the right ventricle, and sends off 
its principal branches to the right side of the heart. 

The other artery of the heart passes between the pulmonary 
artery and the left auricle. It divides into two branches : one, 
which is anterior, passes to a groove on the surface, correspond- 



4gg VESSELS AND NERVES OF THE HEART. 

ing to the septum between the two ventricles, and continues on it 
to the apex of the heart, sending off branches in its course ; 
another, which is posterior and circumflex, passes between the 
left auricle and ventricle. 

The great vein of the heart opens into the under side of the 
right auricle, as has been already mentioned : the main trunk of 
this vein passes for some distance bewteen the left auricle and 
ventricle.* 

From the course of these different vessels round the basis of 
the ventricles of the heart, they are generally called Coronary 
Vessels: the arteries are denominated, from their position, Right 
and Left Coronary. 

The nerves of the heart come from the cardiac plexus, which 
is composed of threads derived from the intercostal or great 
sympathetic nerves, and the nerves of the eighth pair. 

* It was asserted by Vicusscns, at an early period in the last century, and soon 
afterwards by Thebesius, a German Professor, that there were a number of small 
orifices in the texture of the heart, which opened into the different cavities on 
both sides of it. 

This assertion of a fact so difficult to reconcile with the general principles of 
the circulation, was received with great hesitation : and although it was confirmed 
by some very respectable anatomists of the last century, it was denied by others. 
Some of the anatomists of the present day have denied the existence of these ori- 
fices, and some others have neglected them entirely. 

The subject has lately been brought forward in the London Philosophical 
Transactions of 1798, Part I. by a very respectable anatomist, Mr. Abernethy, 
who states that he has often passed a coarse waxen injection from the proper ar- 
teries and veins of the heart into all the cavities of that organ, and particularly into 
the Left Ventricle. But it was only in subjects with diseased lungs that this was 
practicable. 

The existence of this communication between the coronary vessels and the 
great cavities of the heart seems therefore to be proved. The easy demonstration 
in such subjects is ingeniously referred by Mr. Abernethy, to the obstruction of 
the circulation in the lungs ; and he regards the communication as a provision en- 
abling the coronary vessels to unload themselves, when the coronary vein cannot 
discharge freely into the right auricle.* 

* This assertion of Mr. Abernetliy's, lias not been confirmed by subsequent investigations, 
except in cases where the tissue of the heart was softened, and its vessels had been ruptured 
hy the force of the injection.— r. 



GREAT VESSELS OF THE HEART. 



Of the Aorta, the Pulmonary Artery and Veins, and the Vena 
Cavce; at their commencement. 

The two great arteries, which arise from the heart, commence 
abruptly, and appear to be extremely different in their com- 
position and structure from the heart. 

They are composed of a substance, which has a whitish co- 
lour, and very dense texture, and is very elastic as well as firm 
and strong. 

When the pericardium is removed, these arteries appear to 
proceed together from the upper part of the basis of the heart : 
the pulmonary artery being placed to the left of the aorta with 
the left auricle on the left side of it, and the right auricle on the 
right side of the aorta. The pulmonary artery arises from the 
most anterior, and left part of the basis of the right ventricle, 
and proceeds obliquely backwards and upwards ; inclining gra- 
dually to the left side for about eighteen or twenty lines ; when 
it divides into two branches which pass to the two lungs. 

The aorta arises from the left ventricle, under the origin of 
the pulmonary artery, and immediately proceeds to the right, 
covered by that vessel, until it mounts up between it and the 
right auricle: it then forms a great curve, or arch, which turns 
backward and to the left, to a considerable distance beyond the 
pulmonary artery. In this course, it crosses the right branch of 
the pulmonary artery ; and, turning down in the angle between 
it and the left branch, takes a position on the left side of the spine. 
The course of this artery, from its commencement at the ven- 
tricle, to the end of the great curve or arch, is extremely varied. 
The uppermost part of the curve is in the bottom of the 
chamber formed by the separation of the lamina of the medias- 
tinum when they join the first rib on each side. 

From this part of the curve three large branches go off, 
namely, one, which soon divides into the carotid and the sub- 
clavian arteries of the right side ; a second, somewhat smaller, 
which is the left carotid; and a third, which is the left subclavian 

artery. , 

When the heart and its great vessels are viewed from be- 



VOL. I. 



40 



470 



PULMONARY ARTERY AND VEINS. 




dub L 



hind, (after they have all been filled with injection; and the 
pericardium, mediastinum, 

and windpipe have been re- F*g- ^* 

moved,) the aorta appears 
first, descending behind the 
other vessels; the pulmonary- 
artery then appears, dividing 
so as to form an obtuse angle 
with its two great branches, 
each of which divides again 
before it enters the lung to 
which it is destined. 

Under the main trunk of 
the pulmonary artery is the 
left auricle : its posterior sur- 
face is nearly of a square 
form, and each of the pulmo- 
nary veins proceeds from one 
of its angles. These veins 
ramify in the substance of the lungs, at a very short distance 
from the auricle : the two uppermost of them are situated rather 
anterior to the branches of the pulmonary artery. 

In this posterior view, the pulmonary vessels of the right side 
cover a great part of the right auricle, as it is anterior to them. 
The lower portion of the auricle, with the termination of the 
inferior cava, is to be seen below them. Above them the su- 

* Fig. 40. — a, Left ventricle, b, Right ventricle, c, Right auricle. The left 
auricle is seen above the left ventricle of the same side, d, Vena cava inferior, e, 
Subclavian and jugular veins ; those of the left side unite to form the vena trans- 
versa ; those of the right, to form the vena innominata ; the junction of these 
larger trunks, constitutes the vena cava superior or descendens. /, Left carotid. 
g, Left subclavian artery, arising from the arch of the aorta, h, Descending aorta, 
i, k, Right subclavian, and right carotid, given off from the arteria innominata, 
which is seen arising from the arch of the aorta. I, Pulmonary artery, dividing 
into two branches, one for each lung — the left passing in front of the descending 
aorta, the right, behind the aorta, where it begins to form the curve, wi, Vena 
cava superior, n, Aorta, o, Left pulmonary veins, entering auricle of same side. 
The right pulmonary veins, are seen on the opposite side, p, p, Lungs, f, 
Trachea. — p. 



VENiECAV^E. 471 

perior cava appears; and in that part of it which is immediately 
above the right branch of the pulmonary artery, is the orifice of 
the vena azygos. 

In its natural situation in the thorax, the superior cava is con- 
nected by cellular membrane to the right lamen of the medias- 
tinum, and is supported by it. At a small distance below the 
upper edge of the sternum, it receives the trunk formed by the 
left subclavian and internal jugular vein, which passes obliquely 
across the sternum below its inner edge, in the upper space 
between the lamina of the mediastinum. 



472 0F THE TRACHEA. 



CHAPTER XVII. 

OF THE TRACHEA AND THE LUNGS. 

Although the principal part of the windpipe is situated in the 
neck above the cavity of the thorax, it is so intimately connected 
with the lungs, that it is necessary to describe them together. 

Of the Trachea. 

Trachea is the technical name for the windpipe, or the tube 
which passes from the larynx to the lungs. 

This tube begins at the lower edge of the cricoid cartilage, 
and passes down the neck in front of the oesophagus as low as 
the third dorsal vertebra, when it divides into two branches 
called Bronchia, one of which goes to the right and the other to 
the left lung, and ramifies very minutely in them. 

— The right bronchium is larger than the left, in proportion to 
the greater size of the right lung. It is also shorter and placed, 
more anterior, and more horizontal than the left, in consequence 
of the right lung being shorter in its vertical diameter, and longer 
in its antero-posterior than the lung of the left side. It enters 
near the centre of the root of the lung, opposite to the fourth 
dorsal vertebra. 

— The left bronchium terminates or enters the root of the left 
lung, opposite the fifth dorsal vertebras. The right bronchium is 
embraced at its upper part by the vena azygos, the left by the 
arch of the aorta. — 

There is in its structure, a number of flat cartilaginous rings 
placed at small distances from each other, the edges of which 
are connected by membrane, so that they compose a tube. 

These cartilaginous rings are not complete, for they do not 
form more than three-fourths or four-fifths of a circle ; but their 
ends are connected by a membrane which forms the posterior 
part of the tube. 

Thev are not alike in their size or form ; some of them are 



STRUCTURE OF THE TRACHEA AND BRONCHIA. 



473 



rendered broader than others, by the union of two or three rings 
with each other, as the uppermost. The lowermost also is 
broad, and has a form which is accommodated to the bifurcation 
of the tube. Their number varies in different persons, from fif- 
teen to twenty. 

These rings may be considered as forming a part of the first 
proper coat of the trachea; which is composed of them, and of 
an elastic membrane that occupies all the interstice between 
them ; so that the cartilages may be regarded as fixed in this 
membrane. 

A similar arrangement of rings exists in the great branches 
of the bronchia ; but after they ramify in the lungs, the carti- 
lages are no longer in the form of rings : they are irregular in 
their figures, and are so arranged in the membrane, that they 
keep the tube completely open. These portions of cartilage do 
not continue throughout the whole extent of the ramifications; 
for they become smaller, and finally disappear, while the mem- 
branous tube continues without them, ramifying minutely, and 



Fig. 41* 



probably forming the air-cells of 
the lungs. 

This membrane is very elastic : 
the lungs are very elastic also ; and 
it is probable that their elasticity 
is derived from this membrane. 

On the inside of this coat of 
the trachea is an arrangement of 
muscular fibres, which may be 
called a muscular coal. It is best 
seen by peeling off orremovingthe 
internal coat, to be next described. g__ 

On the membranous part of 
the trachea, where the cartilagi- 
nous rings are deficient, these 
muscular fibres run evidently in 
a transverse direction : in the 

* F.<r. 41, represents the larynx, trachea, and bronchia; on the right side is seen 
the lung; on the left, the lung has been destroyed to show the ramification of the 

40* 




474 0F THE TRACHEA. 

spaces between the cartilages their direction is longitudinal. 
There is some reason to doubt whether these longitudinal fibres 
are confined altogether to the spaces between the cartilaginous 
rings, and attached only to their edges, because there is a fleshy 
substance on the internal surface of the rings, which appears to 
be continued from the spaces between them. 

The internal coat of the trachea is a thin and delicate mem- 
brane, perforated with an immense number of small foramina, 
which are the orifices of mucous ducts. 

On the surface of this membrane there is an appearance of 
longitudinal fibres which are not distributed uniformly over it, 
but run in fasciculi in some places, and appear to be deficient in 
others. These fasciculi are particularly conspicuous in the rami- 
fications of the bronchia in the lungs. 

— Many of the German anatomists have described these as 
longitudinal muscular fibres, the object of which is to shorten to 
some extent the air-passages during their contraction, and to as- 
sist in loosening the mucus and other matters which accumulate in 
their cavities. I have examined these carefully in the ox and 
elephant, where they are strongly marked; they appeared to me 
to consist only of longitudinal folds of mucous membrane, with 
a fibro-cellular basis. — 

On the posterior membranous portion of the trachea, where 
the cartilages are deficient, a considerable number of small gland- 
-ular bodies are placed, which are supposed to communicate with 
the mucous ducts that open on the internal surface. If these bo- 
dies are removed from the external surface of this portion, and 
the muscular fibres are also removed from the internal, a very 
thin membrane only remains, which is very different from that 
which is left between the rings, when the fleshy substance is re- 
moved from that situation. 

The reason of the deficiency in the rings, at this posterior part, 
is not very obvious.* It continues in the bronchia until the form 

bronchia, a, Larynx, b, Trachea, dividing into right and left bronchium ; the 
left is the smaller, longer, and inclined most downwards, c, Larger divisions of 
the left bronchium. e, The more minute, d, Right lung. — p. 

* Dr. Physick has advanced the opinion that it enables a person to expel the 



OF THE LUNGS. 475 

of their cartilages is changed in the lungs: if it were only to 
accommodate the oesophagus, during the passage of food, there 
would be no occasion for its extension to the bronchia. 

At the bifurcation of the trachea, and on the bronchia, are a 
number of black-coloured bodies, which resemble the lymphatic 
glands in form and texture. They continue on the ramifications 
of the bronchia some distance into the substance of the lungs. 
Their number is often very considerable ; and they vary in size 
from three or four lines in diameter to eighteen or twenty. As 
lymphatic vessels have been traced to and from them during 
their course to the thoracic duct, they are considered as lym- 
phatic glands. 

Of the Lungs. 

There are two of these organs : each of which occupies one 
of the great cavities of the thorax. 

When placed together, in their natural position, they resemble 
the hoof of the ox, with its back part forward ; but they are at 
such a distance from each other, and of such a figure, that they 
allow the mediastinum and heart to intervene ; and they cover 
every part of the heart anteriorly, except a small portion at the 
apex. 

Each lung fills completely the cavity in which it is placed, and 
every part of its external surface is in contact with some part of 
the internal surface of the cavity ; but when in a natural and 
healthy state, it is not connected with any part except the lamina 
of the mediastinum. 

— The lower extremity or base of each lung, rests upon the 
pleural lining of the diaphragm, and fills up the angle between 
the diaphragm and the ribs ; and the upper projects upwards, 
and backwards, along the first rib above the level of the clavicle, 
so as to be separated from the scalenus anticus muscle, only by 
the pleura. In laborious respiration, the elevation of the apex 
of the lung is increased, and the motion it produces becomes 
visible at the root of the neck. The external face of the lungs 

mucus of the lungs by contracting the size of the trachea, and consequently in- 
creasing the velocity or impetus of the air. — h. 



476 ROOT OF THE LUNGS. 

is concave, to suit the contour of the thoracic parietes. The in- 
ternal and especially that of the left, is concave to accommo- 
date the heart and pericardium. The anterior edge is thin and 
sinuous, and presents on the left side a deep notch fitted to the 
shape of the heart, and a sort of lobular projection which in 
part covers that organ during deep inspiration. — 

One great branch of the trachea and of the pulmonary artery 
passes from the mediastinum to each lung, and enters it at a place 
which is rather nearer to the upper rib than to the diaphragm, 
and much nearer to the spine than the sternum : at this place 
also the pulmonary veins return from the lungs to the heart. 

These vessels are enclosed in a membrane, which is continued 
over them from the mediastinum, and extended from them to the 
lung. Thus covered they constitute what has been called the 
Root of the Lung. 

When their covering, derived from the mediastinum, is re- 
moved, the situation of these vessels appears to be such that the 
bronchia are posterior, the branches of the pulmonary artery are 
rather above and before, and the veins below and before them. 

Each of these vessels ramifies before it enters into the sub- 
stance of the lungs : the bronchia and the branches of the pul- 
monary artery send each a large branch downward to the infe- 
rior part of the lungs, from which the lower pulmonary veins 
pass in a direction nearly horizontal. In general, each of the 
smaller ramifications of the bronchia in the lungs is attended by 
an artery and a vein. 

Each lung is divided, by very deep fissures, into portions which 
are called Lobes. The right lung is composed of three of these 
lobes, and the left lung of two. (See Fig. 40, page 470.) 

— Each of these lobes are subdivided into various smaller 
parts called lobules, which are marked out on the surface of the 
lungs, by various angular lines. Each bronchium divides into 
two principal branches for the lobes of the left lung, and into 
three for the right; after which, a still further subdivision takes 
place, so that a terminal bronchial branch is sent to each 
lobule. — 

The lungs are covered, as has been already stated, with the 



COLOUR OF THE LUNGS. 477 



reflected portion of the pleura continued from the mediastinum, 
which is very delicate and almost transparent. They have, 
therefore, a very smooth surface, which is kept moist by exuda- 
tion from the arteries of the membrane. 

The Colour of the Lungs is different in different subjects. In 
children they are of a light red colour ; in adults they are often of 
a light gray; owing to the deposition of a black pigment in the 
substance immediately under the membranes which form their 
external surface. Their colour is often formed by a mixture of 
red and black. In this case they are more loaded with blood, 
and the vessels of the internal membranes being distended with 
it, the red colour is derived from them. 

The black pigment sometimes appears in round spots of three 
or four lines in diameter : under the external membrane it is 
often in much smaller portions, and sometimes is arranged in 
lines in the interstices of the lobuli, to be hereafter mentioned. It 
is also diffused in small quantities throughout the substance of 

the lungs. 

The source of this substance, and the use of it, are unknown. 

The lungs are of a soft spongy texture ; and, in animals that 
have breathed, they have always a considerable quantity of air 

in them. 

They consist of cells, which communicate with the branches 
of the trachea that ramify through them in every part. These 
cells are extremely small, and the membranes which compose 
them are so thin and delicate, that if they are all filled by an in- 
iection of wax, thrown into the trachea, the whole cellular part 
of the lung will appear like a mass of wax. If a corroded pre- 
paration be made of a lung injected in this manner with force, 
the wax will appear like a concretion. 

These effects of injections prove that the membranes of which 
the cells are formed are very thin; and, of course, that their 
volume is very small when compared with the capacity of the 

cells . r 

' In those corroded preparations, in which the ramifications of 
the bronchia are detached from the wax of the cells, these rami- 
fications become extremely small indeed. 



478 STRUCTURE OF THE LUNGS. 

If the lungs of the human subject, or of animals of similar 
construction, be examined when they are inflated, their cellular 
structure will be very obvious, although their cells are so small 
that they cannot commonly be distinguished by the naked eye. 
Each of the extreme ramifications of the bronchia appears to be 
surrounded by a portion of this cellular substance, which is gra- 
dually distended when air is blown into the ramification. 

This cellular substance is formed into small portions of various 
angular figures, which are denominated Lobuli: these can be 
separated to a considerable extent from each other. They are 
covered by the proper coat of the lungs, which is extremely 
delicate, and closely connected to the general covering derived 
from the pleura. Between the lobuli, where they are in contact 
with each other, there is a portion of common cellular substance, 
which is easily distinguished through the membrane covering the 
lungs. This is very distinct from the cellular structure which 
communicates with the ramifications of the bronchia, and con- 
tains air ; for it has no communication with the air, unless the 
proper coat of the lungs be ruptured. If a pipe be introduced 
by a puncture of the external coat of the lungs, and this inter- 
stitial cellular membrane be inflated, it will compress the lobuli. 
This cellular membrane is always free from adipose matter : it 
may be easily examined in the lungs of the bullock. 

Upon the membranes which compose the air-cells, the pulmo- 
nary artery and vein ramify most minutely ; and it seems to have 
been proved within the last thirty years, by the united labours of 
chemists and physiologists, that the great object of respiration is 
to effect a chemical process between the atmospheric air, when 
taken into the air-cells, and the blood which circulates in these 
vessels. 

In addition to the blood-vessels which thus pass through the 
substance of the lungs, there are several smaller arteries deno- 
minated Bronchial, which arise either from the upper intercostal, 
or from the aorta itself: they pass upon the bronchia, and are 
distributed to the substance of the lungs. The veins which 
correspond with these arteries terminate ultimately in the vena 
azygos. 



STRUCTURE OF THE LUNGS. 479 

The nerves of the lungs are small in proportion to the bulk of 
these organs. They are derived principally from the par vagum 
and the intercostal nerves. 

— They form one plexus on the front, and another on the pos- 
terior surface of the bronchia, along which they are conducted 
to the minutest subdivision of the latter in the substance of the 
lungs. — 

The elasticity of the air-cells of the lungs and of the rami- 
fications of the bronchia which leads to them, is apparent in their 
rapid contraction after distention, and by the force with which 
they expel the air which is used to inflate them when taken out 
of the thorax. 

— The specific gravity of the lungs is not naturally greater 
than that of many other tissues. In a still-born child, sections 
of it sink in water like a piece of muscle. But when its cells 
have been once distended by air in respiration it becomes im- 
possible to extrude it completely, unless it is subjected to strong 
compression, and the lung floats upon the water and appears to 
have the least specific gravity of all the animal tissues. The 
lungs are endowed with a considerable degree of elasticity, 
which appears to be derived from the elastic tissue of the bron- 
chia which is spread universally through the lungs. When dis- 
tended they have a constant tendency either in or out of the 
body to return upon themselves and expel the air. 
—It will now be seen that the proper tissue of the lungs, the 
parenchyma, the areolar tissue, is very complicated. It consists 
of the cells of the bronchia for the reception of air, which are 
formed internally of mucous membrane, and externally most 
probably of a thin expansion of the yellow elastic ligamentous 
layer of the bronchia; of a branch of the pulmonary arteries and 
veins, which run over the outer surface of the cells, the former 
brinoing the black blood, and the latter conveying it away after 
it ha°s been changed by the action of the air through the walls of 
the cells ; of the bronchial arteries and veins for the purpose of 
nutrition'; of absorbent vessels to remove the molecules as they 
become effete; of filaments of the sympathetic and par vagum 
nerves, which preside over the function of hscmoptosis, and put 



480 



THORAX OF THE FCETfJS. 



the lungs in connexion with the brain; and lastly of cellular 
tissue which unites the whole together. 

— Between the bronchial and pulmonary arteries and veins, 
there is an intimate anastomosis so that either system of vessels 
may be filled by the use of fine injecting fluid through the other. 
The cells of each lobule, according to Professor Horner, Cloquet, 
and some other anatomists of distinction, communicate laterally 
with each other. The diameter of these cells has been mea- 
sured by Weber of Leipzig,* by the aid of a micrometer attached 
with extreme care and ingenuity to a microscope. According 
to him they are upon an average about ^ko^h P art of an inch in 
diameter, which makes them five or six times larger than the 
cells of the parotid gland, and fifteen or twenty times larger than 
the finest capillary blood-vessels measured on a portion of 
skin which had been very perfectly injected by Dr. Pockels of 
Brunswick. — 

The Thorax of the Fozlus. 

In the cavity between the lamina of the mediastinum, where 
they approach each other from the first ribs, is situated a sub- 
stance which is denominated the 

Thymus Gland. 

This substance gradually diminishes after birth, so that in the 
adult it is often not to be found : and when it exists it is changed 
in its texture, being much firmer, as well as greatly diminished. 

In the fcetus it is of a pale red colour; and during infancy it 
has a yellowish tinge. It generally extends from the thyroid 
gland, or a little below it, to the pericardium. From its superior 
portion two lateral processes are extended upwards : below, it 
is formed into two lobes, which lie on the pericardium. 

If an incision be made into its substance, a fluid can be press- 
ed out, which has a whitish colour, and coagulates upon the 
addition of alcohol. 

Although it is called a gland, no excretory duct has ever been 
found connected with it. 

* Meckel's Archiv. fur Anat. und Physiol., 1830.— p. 



THE THORAX OF THE FCETUS. 481 

The blood-vessels of this body are derived from the thyroid 
branches of the subclavians, from the internal mammaries, and 
the vessels of the pericardium and mediastinum. 

The Heart, 

And the great arteries which proceed from it, have some very 
interesting peculiarities in the foetus. 

In the septum between the two auricles, is a foramen of suffi- 
cient size to permit the passage of a large quill, which inclines to 
the oval form, with its longest diameter vertical when the body is 
erect. On the left side of the septum, a valve, formed by the 
lining membranes, is connected to this foramen ; and allows a 
free passage to a fluid moving from the right auricle to the left: 
but prevents the passage of a fluid from the left to the right. 
This structure is evidently calculated to allow some of the blood 
which flows into the right auricle from the two venae cavae to 
pass into the left auricle of the heart, instead of going into the 
right ventricle. As the contents of the left auricle pass into the 
left ventricle, and from thence into the aorta, it is obvious that 
the blood which passes from the right auricle into the left through 
this foramen, must be transmitted from the system of the vena 
cava to the system of the aorta, without going through the lungs, 
as it must necessarily do in subjects who do not enjoy the foetal 
structure. 

— The valve, with which in the foetus the foramen ovale is pro- 
vided, on the side of the left auricle, is of a semilunar shape and 
called the valve of Botal ; it has a convex border, adherent, and 
turned downwards ; and a concave border, free, and turned up- 
wards. The angles resulting from the union of these borders are 
attached to each side of the foramen about a quarter of an inch 
distant from each other at birth. The valve makes its appearance 
in the foetus at the third month of intra-uterine existence, and 
gradually increases in size, so as to more than cover the foramen 
at the period of birth. When the child breathes and the lungs 
become filled with blood, the fluid, entering the left auricle by the 
pulmonary veins, throws down the valve against the septum 

41 

VOL. I. ** 



482 



THE THORAX OF THE FCETUS. 



auriculorum, to which its free border usually becomes firmly 
united. 

— Occasionally, however, the union of the parts is found so in- 
complete, even in old persons, as to allow a probe or even the 
handle of a scalpel to be passed obliquely through the opening: 
the obliquity of the orifice being such, as usually to enable it to 
act as a perfect valve. A communication of this sort, of greater 
or less magnitude between the auricles, exists in adults in the ratio 
of one to four. Sometimes the foramen is met with in adults di- 
lated so as to be nearly an inch in diameter. I have met with two 
cases of this sort in the dissecting-room, both of which occurred 
in females between twenty and thirty years of age. The nutri- 
tive functions appeared to have been perfectly well performed in 
both these subjects, judging from the state of the body; the right 
auricle and ventricle were dilated and hypertrophied so as to pre- 
sent the same thickness of parietes as the corresponding parts of 
the left side. The tricuspid valves, and the semilunar valves of the 
pulmonary artery were thickened, and presented cartilaginous con- 
cretions on their edges, in which the work of ossification had just 
commenced. This thickening and ossification of the valves is 
almost wholly peculiar in the normal formation of the heart to 
the valves of the left side, and appears to be caused, as was first 
suggested by Cruveilhier, by the force with which the blood is 
dashed against the valves, in the forcible contractions of the 
ventricle. — 

The Pulmonary Artery and the Aorta 

Have a communication in the foetus, which is very analogous 
to the communication between the auricles of the heart. 

From the pulmonary artery, where it divides into the two 
great branches, another large branch continues, in the direction 
of the main trunk, until it joins the aorta ; with which it com- 
municates at a small distance below the origin of the left sub- 
clavian artery. In the young subject that has never respired, it 
appears as if the pulmonary artery was continued into the aorta, 
and sent off in its course a branch on each side, much smaller 
than itself, to each lung. In subjects that have lived a few days, 



GENERAL OBSERVATIONS. 483 

these branches to the lungs are much larger; and then the main 
pulmonary artery appears to have divided into three branches : 
one to each lung, and one to the aorta ; but that which continues 
to the aorta is larger than either of the others. 

In the course of time, however, this branch of the aorta is 
contracted, so that no fluid passes through it ; and it has the ap- 
pearance of a ligament, in which state it remains. 

The course of the blood from the right ventricle, through the 
pulmonary artery, to the aorta below its curve, is more direct 
than that from the left ventricle to the same spot, through the 
aorta at its commencement. The column of blood in the aorta 
below its curve is evidently propelled by the force of both ven- 
tricles: and this circumstance, although it seems to proceed 
merely from the state of the foetal lungs, is particularly calcu- 
lated for the very extensive circulation which the foetus carries 
on, by means of the umbilical arteries and vein in the placenta. 

The Lungs of the Foetus 

Differ greatly from those of the adult. They appear solid, 
as if they were composed of the parenchymatous substance 
which constitutes the matter of glands, rather than the light 
spongy substance of the lungs of adults. They differ also in 
colour from the lungs of older subjects, being of a dull red. 

They have greater specific gravity than water; but if air be 
once inspired, so much of it remains in them that they ever af- 
terwards float in that fluid. 

The nature of the process of respiration, and its effects upon the animal 
economy, particularly upon the action of the heart, appear to be much 
better understood at this time than they were before the discovery of the 
composition of the atmosphere, by Dr. Priestley and Mr. Scheele. The 
publications upon this subject, which have appeared since that period, 
namely 1774, are therefore much more interesting to the student of medi- 
cine than those which preceded them. Two of these publications ought 
to be particularly noticed by him; namely, an essay, by Dr. Edward 
Goodwyn, entitled, "The Connexion of Life wlt1 ' ^P 1 ^ " ' "^ * 
« Physiological Researches of M. Bichat upon Life and Death. Part 

Second.* 

• The student will derive mueh information respecting the publications on this 
subject, prior to 1804, from Dr. Bostock's Essay on Rcspiration.-S.nce the publi- 



484 CASES OF MALFORMATION. 

The general doctrines respecting the oxygenation or decarbonization of the 
blood and the absolute necessity that it should take place to a certain de- 
gree in order to preserve life, are confirmed by a number of cases of mal- 
formation of the heart or the great vessels, in which the structure was 
such that a considerable portion of venous blood passed from the right 
side of the heart to the aorta, without going through the lungs. In these 
different cases, notwithstanding the structure was somewhat varied, the 
symptoms produced were very much alike; differing in the respective pa- 
tients in degree only, and not in kind. 

The symptoms indicating this structure, are blue colour of the face, (such, 
as generally accompanies suffocation,) extending more or less over the 
whole body, and particularly apparent under the nails of the fingers and 
toes; anxiety about the region of the heart; palpitation; laborious respi- 
ration ; sensations of great debility, &c. : all of which are greatly aggra- 
vated by muscular exertion. These effects have generally appeared to be 
proportioned to the quantity of venous blood admitted into the aortic 
system.* 

When these appearances take place immediately after birth, it is probable 
that they depend entirely upon malformation of the heart or great vessels; 
but when they commence at a subsequent period, they are commonly the 
effect of a diseased alteration in the lungs. They sometimes occur near 
the termination of fatal cases of pneumonia or catarrh ; but a different 
cause, which has not latterly been suspected, appears to have produced 
them in the following case, related by Dr. Marcet, in the first volume of 
the Edinburgh Medical and Physical Journal. 

The blue colour occurred in a young woman, twenty-one years of age, in 
whom it had never been observed before. It came on during an affection 
of the breast, and was attended with great prostration of strength and dif- 
ficulty of breathing ; as well as cough, oedema of the hands and feet, and 
several other symptoms. About seven weeks after the commencement 
of these symptoms, she died ; when it was ascertained by dissection, 

cation of that essay several interesting papers on respiration have appeared, 
namely, Two Memoirs by the late Abbe Spalanzani; "An Inquiry into the 
Changes induced on Atmospheric Air by the Germination of seeds," &c, by Ellis; 
two very important communications by Messrs Allen and Pepys in the Trans- 
actions of the Royal Society of London for 1808 and 1809 ; and "Farther In- 
quiries into the Changes induced on Atmospheric Air," also by Ellis. 

* Cases of this kind are related in several of the periodical publications on me- 
dical subjects. Two of them were described by the late Dr. William Hunter in 
the sixth volume of Medical Observations and Inquiries, by a Society of Physi- 
cians in London ; one quoted by Dr. Goodwyn, is in the Observationes Anatomi- 
cae of Sandifort; and another by Dr. J. S. Dorsey, has lately been published in the 
first number of the New England Journal of Medicine and Surgery. 



EFFECT OF VENOUS BLOOD ON THE HEART. 4Q5 

that there was no unnatural communication whatever between the can- 
ties of the heart, and that its valves were all in a perfect and natural 
state. The lungs were free from tubercles, or any other appearance of 
disease. Their substance seemed more compact than usual, especially 
the left lung, although it did not sink in water; but they adhered every 
where to the inner surface of the thorax, to the diaphragm and to the 
pleura covering the pericardium. — This case is the more remarkable, be- 
cause numberless instances have occurred, in which very large portions 
of the external surface of the lungs have been found, upon dissection, to 
adhere to the internal surface of the thorax, without the occurrence of 
such symptoms during life. 



It may be inferred, from a statement published by M. Dupuytren, in a late 
volume of the Proceedings of the National Institute of France, that the 
oxygenation or decarbonation of the blood is much affected, in respiration, 
by an influence exercised by the nerves which are appropriated to the 
lungs. From his account it appears, that although the complete division 
of the eighth pair of nerves produces death after some time; yet in the 
horse, whose nerves are thus divided, life continues, and respiration goes 
on, from half an hour to ten hours ; but his arterial blood is in a state of 
great disoxygenation or carbonation during this time. This fact is more 
remarkable because venous blood, contained in a bladder exposed to the 
open air, will become oxygenated or decarbonated. 

It is also asserted in another Memoir, read to the National Institute by Dr. J. 
M. Provencal ; that animals, in whom the eighth pair of nerves has been 
divided, do not consume so much oxygen, or produce so much carbonic 
acid, by a considerable degree, as they did before the division of these 
nerves ; and that their temperature is considerably reduced.* 



The effect, that venous blood occasions death, when it is admitted into the 
left ventricle of the heart, and the aorta, is truly important. Dr. Good- 
win explained it by suggesting that this blood was not sufficiently stimu- 
lating to produce the necessary excitement of the heart ; but on this oc- 
casion one of his friends proposed to him the following question : Why 
does venous blood affect the left side of the heart in this injurious manner, 

* These Memoirs are republished in the Eclectic Repertory of Philadelphia for 
April and October, 1811. 

41* 



486 SENTIMENTS OF SABATIER, ETC. 

when it appears to exert no noxious effects whatever on the right side of that 
organ ! His reply may be seen in a note at the 82d page of his Essay, in 
the first edition. Bichat has offered a solution which completely resolves 
this difficulty, viz. " The effect of venous blood upon the heart is pro- 
duced by the presence of this blood in the proper, or coronary arteries of 
that organ, and not in its great cavities." For the animation of the heart, 
like that of the other parts of the body, depends upon the state of the 
blood in the arteries which penetrate its texture.* And while the heart 
acts, the blood of the coronary arteries will be the same with that of the 
left ventricle. See Bichat's Researches, P. II. art. 6, J 2. 
The French anatomists appear to entertain some peculiar opinions respect- 
ing the course of the blood in the foetus, which have a particular relation 
to the subject last mentioned. Winslow, who paid great attention to the 
valve of Eustachius in the right auricle of the heart, was of opinion, that 
this valve was calculated for some important purpose in the fetal econo- 
my.! Although his hypothesis respecting its particular use has not been 
retained by his countrymen, many of them have adopted his general sen- 
timent ; and among others Sabatier. That learned anatomist believed 
that this valve, in the fetal state, serves to direct the blood of the infe- 
rior cava, after its arrival in the right auricle through the foramen ovale 
into the left auricle ; while the blood of the upper cava passes directly 
into the right ventricle. His opinion seems to be supported to a certain 
degree — 

1. By the direction in which the two columns of blood enter the auricles 
from the two venae cava?. 

2. By the position of the Eustachian valve. 

8. By the foramen ovale, when its valve is complete ; as the passage 
through it from the right to the left, is at that time oblique, and from 
below upwards. 
The theory of Sabatier appears to be this:— the umbilical vein brings from 
the placenta blood which has a quality essential to the animation of the 
fetus. If there were no particular provision to the contrary, a large por- 
tion of this blood, after passing from the umbilical vein by the inferior 
cava into the right auricle of the heart, would proceed by the right ven- 
tricle through the pulmonary artery and arterial canal, into the aorta, be- 
low the origins of the carotid and subclavian arteries ; and consequently 
none of it would pass to the head and upper extremities, but a considerable 

* It is probable that the contents of the great cavities of the heart have no more 
effect upon its animation than the contents of the stomach and bowels have upon 
the animation of those organs. 

t See Memoirs of the Academy of Sciences for 1717 and 1725. 



SENTIMENTS OF SABATIER, ETC. 4Q7 

part would return again by the umbilical arteries to the placenta, with- 
out circulating through the body : while, on the other hand, the blood 
which passed by the carotid and subclavian arteries to the head and up- 
per extremities returning from them to the heart by the superior cava, 
might pass from the right auricle to the left auricle and ventricle and the 
aorta, and so to the head and upper extremities again, without passing 
through the placenta. But by means of this valve, the blood of the lower 
cava, and of course of the umbilical vein, is directed to the left auricle 
and ventricle and the aorta, by which a considerable portion of it will ne- 
cessarily pass to the head and upper extremities ; while the blood which 
returns from these parts by the superior cava, must consequently pass 
from the right auricle into the right ventricle and pulmonary artery ; from 
whence a large portion of it will proceed through the arterial canal into 
the aorta beyond the carotids and subclavians, and of this portion a con- 
siderable part will go to the placenta by the umbilical arteries. Sabatier 
compares the course of the blood in the foetus to the course of a fluid in a 
tube which has the form of the numeral character 8.* If this doctrine be 
true, the progress of the blood in the fetus and placenta is very analogous 
to that of the double circulation of the adult ; the character 8 answering 
equally well in the description of either subject. 
According to Sabatier, the blood of the placenta takes this peculiar course 
through the heart, in order that some of it may be carried to the head and 
upper extremities. But an additional reason may be suggested, which 
appears to be of great importance; namely, the supplying of the coronary 
or proper vessels of the heart with some of the same blood. 
The heart of the adult, as has been before stated, cannot act without its pro- 
per or coronary arteries are supplied with arterial blood. The heart of 
the fetus performs a more extensive circulation than that of the adult, 
and, therefore, is probably in greater need of such blood. But unless the 
blood of the placenta pass through the foramen ovale into the left auricle 
and ventricle, and so to the aorta, it cannot enter the coronary arteries 
which originate at the commencement of the aorta ; for the blood which 
flows from the right side of the heart through the arterial canal, passes 
into the aorta at so great a distance from the orifices of the coronary ar- 
teries, that it certainly cannot enter them. 
The whole of this doctrine seems to be supported by a fact very familiar to 
accoucheurs, viz. the occurrence of death in the fetus whenever the cir- 
culation through the umbilical cord is suspended during fifteen or twenty 
minutes; for as the placenta imparts to the fetal blood a quality essential 
to life, some arrangement seems necessary to provide for the equal distri- 

* Sec Sabatier's Paper on this subject, in the Memoirs of the Academy of Sci- 
ences, for 1774. 



488 UNUSUAL CASES OP MALFORMATION. 



bution of the blood which comes from this organ, and especially for carry- 
ing the requisite proportion of it to the substance of the heart. 



Life has existed for some time with a structure very different indeed from 
that which is natural. In the series of elegant engravings relating to 
morbid anatomy, published by Dr. Baillie, is the representation of a heart, 
in which the vena? cavse opened into the right auricle, and the pulmonary 
veins into the left auricle, in the usual manner; but the aorta arose entirely 
from the right ventricle, and the pulmonary artery as completely from the 
left. The canalis arteriosus, however, passed from the pulmonary artery 
to the aorta, and the foramen ovale existed. In this case, it is evident, that 
the pulmonary artery must have carried back to the lungs the arterial blood 
which came from them by the pulmonary veins, with a small quantity of 
venous blood that passed into the left auricle through the foramen ovale ; 
and that the aorta must have returned to the body the venous blood, which 
just before had been brought from it by the venae cavae, with a small ad- 
dition of arterial blood that passed through the ductus arteriosus. Yet 
with this structure the child lived two months after its birth. 

A case, which had a strong resemblance to the foregoing, occurred lately in 
Philadelphia, and was examined by the author of this work. The venae 
cavas terminated regularly in the right auricle, and the pulmonary veins 
in the same regular manner in the left; but the pulmonary artery arose 
from the left ventricle, and the aorta from the right. There was no com- 
munication between these vessels by a canalis arteriosus ; but a large 
opening existed in the septum between the auricles. 

It is very evident, that, in this case also the pulmonary artery must have 
returned to the lungs the arterial blood as it came from them, and the aorta 
must have carried back to the general system the venous blood brought to 
the heart by the cava? ; excepting only those portions of the arterial and 
venous blood which must have flowed reciprocally from one auricle into 
the other, and thus changed their respective situations. 

The subject was about two years and a half old. The heart was nearly 
double the natural size, and the foramen, or opening in the septum between 
the auricles, was eight or nine lines in diameter. The pulmonary artery 
was larger in proportion than the aorta or the heart. 

With this organization, the child lived to the age above specified. His 
countenance was generally rather livid; and this colour was always much 
increased by the least irregularity of respiration. His nails were always 
livid. He sometimes appeared placid, but more frequently in distress. He 
never walked, and seldom, if ever, stood on his feet. When sitting on 
the floor, he would sometimes push himself about the room ; but this 
muscular exertion always greatly affected his respiration. He attained 



FORAMEN OVALE. 489 

the size common to children of his age, and had generally a great appetite. 
For some weeks before death his legs and feet were swelled. 
It is probable that the protraction of life depended upon the mixture of 
the blood in the two auricles ; and that they really were to be considered 
as one cavity, in this case. 



There seems reason to believe, that in adults of the common structure, there 
is no passage of blood from one auricle to the other, when the foramen 
ovale has remained open; because in several persons in whom it was found 
by dissection to have remained open, there were no appearances during 
life, that indicated the presence of disoxygenated blood in the aortic 
system. It is probable, that the small size of the foramen ovaie, the 
valvular structure which generally exists there, and the complete occupa- 
tion of the left auricle by the blood flowing from the pulmonary veins, 
prevent the passage of blood from the right auricle to the left, in such 
persons; whereas in the case in question, the opening between the auricles 
was very large indeed, and there was no appearance of a valve about it. 

Although it be admitted, that in adults with the foramen ovale pervious, 
there is no transmission of blood from the right to the left auricle ; there 
is every reason to believe, that this transmission goes on steadily in the 
foetus To the arguments derived from the structure and the nature of 
the case, it may be added, that the pulmonary veins, in the fetal state, 
carry to the left auricle a Quantity of blood, not sufficient to fill it; while 
the venffi cava? carry to the right auricle, not only the whole blood of the 
body, but of the umbilical cord and placenta : some of which must flow 
into the unfilled left auricle, when the right auricle becomes fully dis- 
tended. 



The question, how far the functions of the heart and lungs are dependent 
upon the brain, is very important, and has often been agitated with great 
zeal. In favour of the opinion that the motions of the heart are indepen- 
dent of the brain, may be stated the numerous cases in which the .brain 
has been deficient in children, who have notwithstanding ived the full 
pe nod o? utero-gestation, and even a short time after birth, and have armed 
at"heir full size, with every appearance of perfect vigour and action in 
tne heart In support of the doctrine, that the action of the heart is im- 
m d ate y dependent upon the brain, it may be observed, that no organ o 
The Toly arrears to be so much influenced by passions and other mental 



490 0N THE S0URCE OF THE MOTION OF THE HEART. 

affections as the heart. These contradictory facts have occasioned this 
question to be considered as undecided, if not incapable of solution; although 
Cruikshank and Bichat* have stated circumstances very favourable to the 
opinion that the motions of the heart are independent of the brain. 



This question seems now to be settled by the experiments of Dr. Legal- 
lois, a physician of Paris, which prove, that in animals who have suffered 
decapitation, the action of the heart does not cease as an immediate conse- 
quence of the removal of the head ; but its cessation is an indirect effect, 
induced by suspension of respiration. That respiration is immediately 
affected by decapitation, and depends upon the influence of the brain 
transmitted through the eighth pair of nerves. That the action of the 
heart will continue a long time after decapitation, if inflation of the lungs, 
or artificial respiration, be performed ; but, on the contrary, if the spinal 
marrow be destroyed, the action of the heart ceases irrecoverably. 

The inference from these experiments seems very conclusive, that the 
Spinal Marrow, and not the brain, is the source of the motions of the 
heart. 

It appears also by some of the experiments, that the power of motion 
in the trunk of the body, is derived from the spinal marrow; and that, 
when this organ is partially destroyed, the parts which receive nerves 
from the destroyed portion soon cease to live. By particular manage- 
ment of the spinal marrow, one part of the body can be preserved alive 
for some time after the other parts are dead. 

These experiments of Dr. Legallois, commenced in 1806, or 1807, and 
were communicated to the imperial Institute of France, in 1811. The 
committee of that body, to whom they were referred, namely, Messrs. 
Humboldt, Halle, and Percy, reported that the experiments had been re- 
peated before them, at three different meetings of several hours each; and 
that, to allow themselves sufficient time for reflection, they suffered an 
interval of a week to take place between the meetings. The committee 
believe these experiments to have proved, 

1st. That the principle upon which all the movements of inspiration 
depend, has its seat about that part of the medulla oblongata from which 
the nerves of the eighth pair arise. 

* See Cruikshank's Experiments on the Nerves and Spinal Marrow of living 
Animals; London Philosophical Transactions for 1795. The eighth experiment 
has a particular relation to this subject. Bichat's Researches, part 2, article 9. 

The Abbe Fontana has considered this subject in his Treatise on the Venom of 
the Viper, vol. ii. page 194, English translation ; and also in some of his other 
works. 



HUMBOLDT AND OTHERS ON LEGALLOIS' PAPER. 49} 

2d. That the principle which animates each part of the trunk of the 
body, is seated in that portion of the spinal marrow from which the nerves 
of the part arise. 

3d. That the source of the life and strength of the heart is also in the 
spinal marrow ; not in any distinct portion, but in the whole of it. 

4th. That the great sympathetic nerve is to be considered as originating 
in the spinal marrow, and that the particular character of this nerve is 
to place each of the parts to which it is distributed under the immediate in- 
fluence of the whole nervous power. 
The interesting memoir of Dr. Legallois is confirmed to a certain degree 
by a communication of B. C. Brodie to the Royal Society of London in 
1810, in which are detailed many very interesting experiments, which 
induced the author to conclude, — 

That the influence of the brain is not directly necessary to the action 
of the heart ; and 

That when the brain is injured or removed, the action of the heart 
ceases only because respiration is under its influence ; and if, under these 
circumstances, respiration is artificially produced, the circulation will still 
continue. 
These various experiments apply particularly to the cases in which the 
brain is deficient. The effects of mental agitation on the heart are like- 
wise reconcilable to the theory which arises out of them. But they throw 
no light on the question why the motions of the heart are so perfectly free 
from the influence of the will : and although they seem to prove incon- 
testably that the motion of the heart is independent of the brain, it ought 
to be remembered that in certain diseased states of the brain, where that 
organ appears to be compressed, the action of the heart is often very irre- 
gular, and its contractions less frequent than usual. 



END OF VOL. I.